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1

Tides and Decadal Variability  

NASA Technical Reports Server (NTRS)

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."

Ray, Richard D.

2003-01-01

2

Weather sends red tide packing  

NSDL National Science Digital Library

This Mobile Register newspaper article provides general information about the impact of a cold front on red tide in Alabama. Red tide in the area had been rising until the front passed through, killing most of the phytoplankton bloom.

Finch, Bill; Register, Mobile

3

Changing Sea Levels: Effects of Tides, Weather and Climate  

NASA Astrophysics Data System (ADS)

Variability in sea level is one of the most readily observable dynamic features of the coastal ocean, obvious to the most casual beachgoer, and of concern to a rapidly growing portion of the world population. Sea level varies on an astoundingly large variety of scales, from surface waves and seiches, tides, storm surge, to longer-term variability, both man-made and natural. All of these sources of variability are not only of scientific interest but also of great societal importance, due to the ever-increasing percentage of the human population living in coastal regions. David Pugh's clearly written and cleanly presented new book, Changing Sea Levels: Effects of Tides, Weather and Climate, covers these topics at a level of sophistication appropriate for an undergraduate science course. The book is rich in the history, lore, and culture of tides and other sea level phenomena, and discusses the ecological and societal impacts of sea level change across the spectrum of phenomena.

Austin, Jay

2004-11-01

4

Lunar Tide Variability in Thermosphere Density as Derived from GOCE, CHAMP and GRACE Accelerometer Data  

NASA Astrophysics Data System (ADS)

Study of the lunar tide in the ionosphere has a long history, and new discoveries are still being made, e.g., in connection with sudden stratosphere warmings and the equatorial electrojet, for instance. However, only recently have sufficient observations been available to delineate the neutral-atmosphere lunar tide and its variability on a global scale. In this paper we discuss extraction of the lunar tide from accelerometer measurements on the GOCE, CHAMP and GRACE satellites at nominal altitudes of 260, 350 and 450 km, respectively, from both climatological and space weather perspectives. Despite near-constant forcing, the weather aspects of the lunar tide arise from its sensitivity to background atmosphere conditions, which change in response to meteorological conditions and variable solar and magnetospheric inputs. There are significant challenges in separating the lunar tide from density variability due to changing geomagnetic conditions, especially recurrent geomagnetic activity with a period of 13.5 days, which are briefly described. We find that thermosphere density variations attributable to the lunar tide (~5-7%) at 260 km during 2009-2011 are about half those due to the the background "weather" due to geomagnetic activity; amplitudes at CHAMP and GRACE altitudes can be twice as large. Although of sufficient magnitude to be relevant to prediction of satellite ephemerides and inherently predictable in a climatological sense, the lunar tide has not been included in any empirical models to date.

Forbes, Jeffrey; Zhang, Jesse; Doornbos, Eelco; Bruinsma, Sean; Zhang, Xiaoli; Zhang, Casey

2014-05-01

5

Solar variability, weather, and climate  

NASA Technical Reports Server (NTRS)

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.

1982-01-01

6

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

7

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

USGS Publications Warehouse

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.

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

2014-01-01

8

Tides  

NSDL National Science Digital Library

This data tip from Bridge, the Ocean Sciences Education Teacher Resource Center archive, focuses on tides. Students learn how to plan for tide-affected activities by using the NOAA Tide Predictions page to calculate tidal predictions for several days at a site of interest in the coastal United States. Students are also linked to a site with global data where they may generate a graph of tidal predictions for a location near them. Several other educational sites are referenced.

2000-08-01

9

Weather variability, climatic change, and soybean production  

SciTech Connect

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.

Thompson, L.M.

1985-01-01

10

Inter-annual Variability of Nonmigrating Tides Forced by Tropical Convection  

NASA Astrophysics Data System (ADS)

Current observations and models demonstrate unequivocally that non-Sun-synchronous (nonmigrating) tides due to deep tropical convection produce large longitudinal and local time variations in bulk ITM properties, i.e., temperature, wind, composition and plasma density, to name a few. We thus stand at an exciting research frontier: understanding how persistent, large-scale tropospheric weather systems affect Earth's upper atmosphere and geospace environment. One science challenge question is the inter-annual variability of the nonmigrating tides. This paper focusses on quasi-biennial and longer term tidal variations presumably induced by the QBO and the solar cycle. Multiple years of satellite-borne tidal temperature and wind observations show considerable amplitude variations on these time-scales, from the MLT region (SABER and TIDI on TIMED) to the upper thermosphere (CHAMP and GRACE). The results are interpreted using an empirical fit model and the WACCM general circulation model. Possible implications for the thermospheric energy budget are discussed.

Oberheide, J.; Forbes, J. M.; Smith, A. K.; Marsh, D. R.

2009-05-01

11

Economic impacts of weather variability  

Microsoft Academic Search

The report documents and provides a quantitative analysis of the interactions between weather and weather-sensitive enterprises. The following weather-dependent relationships are examined: (1) Agriculture with analysis by various crops; (2) forest fire; (3) energy, both demand and alternative energy sources; (4) outdoor activities, including construction, farm machinery, transportation, and recreation; and (5) health of humans, farm animals, and crops. A

McQuigg

1975-01-01

12

Tides  

NASA Astrophysics Data System (ADS)

This book provides a history of the study of the tides over two millennia, from the primitive ideas of the Ancient Greeks to present sophisticated space-age techniques. Tidal physics has puzzled some of the world's greatest scientists and mathematicians: Galileo, Descartes, Bacon, Kepler, Newton, Bernoulli, Euler, Laplace, Young, Whewell, Airy, Kelvin, G. Darwin, Lamb. The book will appeal to all those interested in how scientific ideas develop. It will particularly interest specialists in oceanography, hydrography, geophysics, geodesy, astronomy and navigation.

Cartwright, David Edgar

2000-08-01

13

Interannual variability of Martian weather  

Microsoft Academic Search

Pressure, temperature, imaging, and wind data from the Mutch Memorial Station, the Viking lander located in Mars' subtropics, are used to demonstrate the existence of two disctinct regimes of northern hemisphere winter weather on Mars. One of these regime is characterized by one or more intense global dust storms in which the optical depth reaches about 5 over most of

C. B. Leovy; J. E. Tillman; W. R. Guest; J. Barnes

1985-01-01

14

Tides and Tide Prediction  

NSDL National Science Digital Library

This tide and tide prediction resource directory links to online tide predictors, tide observations/sea level measurements, tide prediction software you install to generate tide predictions on demand, and general information on tides and tide prediction.

Brueggeman, Peter

1999-01-01

15

Energetics and temporal variability of internal tides in Luzon Strait: a nonhydrostatic numerical simulation  

NASA Astrophysics Data System (ADS)

A fully nonlinear, three-dimensional nonhydrostatic model driven by four principal tidal constituents (M2, S2, K1, and O1) is used to investigate the spatial-temporal characteristics and energetics of internal tides in Luzon Strait (LS). The model results show that, during spring (neap) tides, about 64 (47) GW (1 GW=109 W) of barotropic tidal energy is consumed in LS, of which 59.0% (50.5%) is converted to baroclinic tides. About 22 (11) GW of the derived baroclinic energy flux subsequently passes from LS, among which 50.9% (54.3%) flows westward into the South China Sea (SCS) and 45.0% (39.7%) eastward into the Pacific Ocean, and the remaining 16 (13) GW is lost locally owing to dissipation and convection. It is revealed that generation areas of internal tides vary with the spring and neap tide, indicating different source areas for internal solitary waves in the northern SCS. The region around the Batan Islands is the most important generation region of internal tides during both spring and neap tides. In addition, the baroclinic tidal energy has pronounced seasonal variability. Both the total energy transferred from barotropic tides to baroclinic tides and the baroclinic energy flux flowing out of LS are the highest in summer and lowest in winter.

Li, Mingjie; Hou, Yijun; Li, Yuanlong; Hu, Po

2012-09-01

16

Barometric Tides from ECMWF Operational Analyses  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

17

Interannual Variability of Diurnal Tropospheric Heating and Diurnal Tides  

NASA Astrophysics Data System (ADS)

We present analyses of tropospheric diurnal heating, and middle atmosphere diurnal tides. Our study highlights interannual variations, which have received comparatively little attention in the literature compared with seasonal studies. Analyses of 12 years of data from the Kauai MF radar and 8 years of data from the Christmas Island MF radar reveal significant interannual amplitude enhancements in the diurnal tide, particularly during 1992 and 1997. The amplitude maximum in 1997 is correlated with above-average tropical tidal heating due to IR absorption by water vapor. The tidal heating was derived using the NASA Water Vapor Project (NVAP) climatology. Examination of 10 years of monthly averaged tropospheric diurnal water vapor heating reveals an interannual component that maximizes over the Indian and tropical central Pacific oceans. This component explains over 40% of the total variance in the 10-year diurnal climatology of water vapor heating. We also explore the role of convective heating in modulating tropospheric diurnal forcing.

Riggin, D. M.; Lieberman, R. S.

2003-12-01

18

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

19

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

20

Atmospheric tides forced by troposphere heating: Longitudinal variability of upper atmosphere consequences  

NASA Astrophysics Data System (ADS)

This PhD work is motivated by the unprecedented observations provided by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument on the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) spacecraft. Through creative methods that avoid aliasing problems between tidal variations and mean background temporal variations, a fairly clear picture of both migrating and nonmigrating solar thermal tides from the stratosphere to the MLT (Mesosphere and Lower Thermosphere) region is obtained. The background structures in zonal mean temperatures, geopotential, and the zonal mean gradient zonal winds are also achieved. By retrieving net radiative heating rate profiles from the most updated solar radiative fluxes provided by ISCCP/NASA-GISS (International Satellite Cloud Climatology Project/NASA Goddard Institute for Space Studies) and constructing latent heating rate profiles from the most recent TRMM/NASA-GSFC (Tropical Rainfall Measuring Mission/NASA Goddard Space Flight Center) daily latent heating profiles and 3-hourly TRMM rainfall rates, total tropospheric tidal heating rate profiles are obtained. The Global Scale Wave Model (GSWM) is thus updated with the new tropospheric heat sources and observed mean background inputs to result in the latest version of GSWM, GSWM-09. By comparing GSWM-09 and SABER tidal signatures, the importance of troposphere heat energy in driving atmospheric tides in the MLT region is confirmed and the relative importance of radiative and latent heat sources for migrating and nonmigrating tides is demonstrated with emphasis on longitudinal variability of MLT tides. It confirms that the eastward-propagating diurnal tide with zonal wave number 3 is the outstanding nonmigrating tide due to the topography-modulated tropospheric heating. The critical factors for the seasonal-latitudinal variations of DE3 are examined based on classical tidal theory and its modern developments, since these variations are much improved in GSWM-09, taking observed SABER tidal signatures as the reference. It demonstrates that both mean zonal wind and tropospheric heating are critical in determining the seasonal-latitudional variations of DE3.

Zhang, Xiaoli

21

Theoretical variability of s1 in the tide generating potential  

NASA Astrophysics Data System (ADS)

The S1 tidal wave arising from the second order tidal potential occurs in any geophysical data record. Since the frequency of S1 is the same as that of earth’s rotation, many distortions are observed in real data sets. To isolate S1 from its powerful neighbours, K 1 and P1 at least one-year hourly data series are required. Studies on S 1 on an experimental basis, have been aimed mainly at a precise determination of its origin and mechanisms of variability. There are many hypotheses on its variability. In physical oceanography it is commonly accepted that the variability of S1 is due to air-sea interaction processes. The authors review most existing hypotheses on the variability of S1 They also show that the distortions of real data must be expected due to additional contributions from the second and third-order lunar potentials. An analysis is made to detect the sources of the additional contributions to the S1 frequency.

Alonso, J. J.; Bruno, M.; Mañanes, R.

1997-12-01

22

Temporal variability of internal tides in the northeast South China Sea  

NASA Astrophysics Data System (ADS)

The northeast South China Sea is perhaps the largest internal tide energy source in the world. The temporal variability of internal tides was investigated on the basis of 8-month moored acoustic Doppler current profiler observations on the continental slope at the Dongsha Plateau. The daily amplitude and phase of diurnal and semidiurnal internal tides were determined from complex demodulation, and the dominant spatial and temporal patterns were extracted with empirical orthogonal function (EOF) analysis. The EOF modal structures showed good agreement with the normal mode solution, although vertical phase propagations were apparent. The first semidiurnal EOF mode corresponded to the first normal mode, and the first two diurnal EOF modes corresponded to the second and third normal modes, respectively. The modal structure and energy flux also were consistent with previous observations near the shelf break from the Asian Seas International Acoustic Experiment. On the other hand, the amplitudes of diurnal and semidiurnal EOF modes both indicated large irregular fortnightly variations that were not phase locked (incoherent) with astronomical forcing. The study highlighted the importance of incoherent internal tidal motion, which accounted for about three fourths of the observed tidal energy.

Lee, I. Huan; Wang, Yu-Huai; Yang, Yih; Wang, Dong-Ping

2012-02-01

23

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

24

Spatially variable erodability in bedrock channels produced by weathering  

Microsoft Academic Search

Erosion of bedrock-floored channels regulates the evolution of many landscapes, and accurate prediction of channel erosion rates is a primary goal of landscape evolution modeling. We hypothesize that bedrock weathering, typically neglected in models of bedrock channel evolution, introduces spatial variation in the rock erodability across such channels. The variability of erodability, in turn, may influence the equilibrium cross-sectional form

B. Murphy; G. S. Hancock; E. E. Small

2009-01-01

25

Understanding Tides  

NSDL National Science Digital Library

In this activity students investigate tidal phenomena by exploring water level observational (or predicted tidal) data from several locations around the world that provide examples of semi-diurnal, diurnal, and mixed tides. Students are asked to identify patterns of variability and differences among the sites on time scales of just a few days and over a period of a couple months. The activity is designed more to get students thinking about tides, asking questions about the causes of tidal variations, and thinking about ways to answer these questions, as opposed to providing an explanation of tidal processes. The activity leads to a body of observations that generate numerous questions about tides. The goal is to capture student's interest before spending subsequent class time developing a conceptual/theoretical model of how tides work.

Cook, Tim

26

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

NASA Astrophysics Data System (ADS)

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-situ data in the southern part of the basin represent a major point of weakness of this study and in general affects the significance of the studies about sea level in the Mediterranean sea.

Bonaduce, A.; Pinardi, N.

2012-04-01

27

Understanding Space Weather: The Sun as a Variable Star  

NASA Technical Reports Server (NTRS)

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

Strong, Keith; Saba, Julia; Kucera, Therese

2012-01-01

28

Understanding Space Weather: The Sun as a Variable Star  

NASA Technical Reports Server (NTRS)

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

Strong, Keith; Saba, Julia; Kucera, Therese

2011-01-01

29

Initialisation of Land Surface Variables for Numerical Weather Prediction  

NASA Astrophysics Data System (ADS)

Land surface processes and their initialisation are of crucial importance for Numerical Weather Prediction (NWP). Current land data assimilation systems used to initialise NWP models include snow depth analysis, soil moisture analysis, soil temperature and snow temperature analysis. This paper gives a review of different approaches used in NWP to initialise land surface variables. It discusses the observation availability and quality, and it addresses the combined use of conventional observations and satellite data. Based on results from the European Centre for Medium-Range Weather Forecasts (ECMWF), results from different soil moisture and snow depth data assimilation schemes are shown. Both surface fields and low-level atmospheric variables are highly sensitive to the soil moisture and snow initialisation methods. Recent developments of ECMWF in soil moisture and snow data assimilation improved surface and atmospheric forecast performance.

de Rosnay, Patricia; Balsamo, Gianpaolo; Albergel, Clément; Muñoz-Sabater, Joaquín; Isaksen, Lars

2014-05-01

30

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

NASA Astrophysics Data System (ADS)

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 melt [5]. We end by presenting preliminary results from such an analysis. [1] Sallenger et al. (2012), Nat. Clim. Change 2: 884-888. [2] Kopp (in press),Geophys. Res. Lett. [3] Engelhart and Horton (2011), Quat. Sci. Rev. 54: 12-25. [4] Kemp et al. (2011), Proc. Natl. Acad. Sci. 108: 11017-11022. [5] Hay et al. (2013). Proc. Natl. Acad. Sci. 110: 3692-3699.

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

2013-12-01

31

Assessment of natural climate variability using a weather generator  

NASA Astrophysics Data System (ADS)

It is common practice to use a 30-year period to derive climatological values, as recommended by the World Meteorological Organization. However this convention relies on important assumptions, of which the validity can be examined by deriving the uncertainty inherent to using a limited time-period for deriving climatological values. In this study a new method, aiming at deriving this uncertainty, has been developed with an application to precipitation for a station in Europe (Westdorpe) and one in Africa (Gulu). The weather generator framework is used to produce synthetic daily precipitation time-series that can also be regarded as alternative climate realizations. The framework consists of an improved Markov model, which shows good performance in reproducing the 5-day precipitation variability. The sub-seasonal, seasonal and the inter-annual signals are introduced in the weather generator framework by including covariates. These covariates are derived from an empirical mode decomposition analysis with an improved stability and significance assessment. Introducing covariates was found to substantially improve the monthly precipitation variability for Gulu. From the weather generator, 1,000 synthetic time-series were produced. The divergence between these time-series demonstrates an uncertainty, inherent to using a 30-year period for mean precipitation, of 11 % for Westdorpe and 15 % for Gulu. The uncertainty for precipitation 10-year return levels was found to be 37 % for both sites.

Brisson, Erwan; Demuzere, Matthias; Willems, Patrick; van Lipzig, Nicole P. M.

2014-04-01

32

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

33

Dynamic and regression modeling of ocean variability in the tide-gauge record at seasonal and longer periods  

NASA Astrophysics Data System (ADS)

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.

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

2007-05-01

34

The influence of ocean tide model corrections on geosat mesoscale variability maps of the north east Atlantic  

NASA Astrophysics Data System (ADS)

A two year GEOSAT radar altimeter dataset has been analysed by repeat profile methods to produce mesoscale variability maps of the North East Atlantic. Significant differences have been found between maps produced using two different ocean tide models for corrections to the sea surface height measurements. The area of the Iceland-Faeroes Front is particularly affected. Large values of sea surface height variability found here when the Schwiderski ocean tide model is used, are considerably reduced when a model developed by Flather is used. The latter model is known to be more accurate overall for the north east Atlantic region. The fact that model errors can produce mesoscale variability values larger than those expected from the frontal processes emphasises once again the need for a general improvement in tidal knowledge.

Tomas, J. P.; Woodworth, Philip L.

1990-12-01

35

Global structure, seasonal and interannual variability of the eastward propagating tides seen in the SABER\\/TIMED temperatures (2002–2007)  

Microsoft Academic Search

The present paper is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the most stable in amplitude and phase eastward propagating diurnal and semidiurnal tides with zonal wavenumbers 2 and 3 derived from the SABER\\/TIMED temperatures for full 6years (January 2002–December 2007). The tidal results are obtained by an analysis method where the tides

D. Pancheva; P. Mukhtarov; B. Andonov

2010-01-01

36

Global structure, seasonal and interannual variability of the migrating semidiurnal tide seen in the SABER\\/TIMED temperatures (2002-2007)  

Microsoft Academic Search

The present paper is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the migrating semidiurnal tide derived from the SABER\\/TIMED temperature measurements for 6 years (January 2002-December 2007). The tidal results are obtained by a new analysis method where the tides (migrating and nonmigrating) and the planetary waves (zonally travelling and stationary) are simultaneously

D. Pancheva; P. Mukhtarov; B. Andonov

2009-01-01

37

Tide generator  

SciTech Connect

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.

Feltenberger, B.D.

1981-06-16

38

Weather  

NSDL National Science Digital Library

This is a first grade weather unit. SEASONS Fall Winter Build a Snowman Spring Summer What things determine and effect the weather? Cloud Precipitation Sunshine Temperature Visibility Wind Direction Wind Force WEATHER VIDEOS Tornado Hurricane Hail Lightning FUN AND GAMES Dress the Bear for the Weather The Great Weather Race Game Weather coloring books for kids ...

Stearns, Ms.

2008-10-25

39

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

40

Weather  

NSDL National Science Digital Library

Have you ever wondered how the weather man, or meteorolgist, on TV knows what to say about tomorrow\\'s weather? It\\'s because they have certain tools that they use that help them predict what the weather will be. Throughout this school year you are going to be making tools and predicting weather just like a meterorologist! Task You are going to be weather forcasters! You are going to record and track weather patterns throughout the year. You will also use weather tools to make predictions about the weather like real weather forecasters! The Process 1. First we need to learn a little bit about weather so ...

Williams, Ms.

2005-10-25

41

NOAA Tides Online  

NSDL National Science Digital Library

Access weather and water level observations for stations across coastal United States and the Great Lakes. Follow the "CO-OPS Website" link for tide predictions, additional weather-related observations, publications, and much more. Historical data is available for download. Site provides emergency information when a station's water level exceeds normal and is activated into Storm Surge mode.

42

Space Weather Products from the Extreme Ultraviolet Variability Experiment (EVE)  

NASA Astrophysics Data System (ADS)

A majority of the solar flare energy is released in the hard x-ray (HXR), soft x-ray (SXR), and extreme ultraviolet (EUV) ranges, and thus these wavelengths are an important measure of solar activity for myriad of space weather applications and operations. The EUV Variability Experiment (EVE) aboard NASA's Solar Dynamics Observatory (SDO) is observing the solar SXR and EUV irradiance continuously from its GEO orbit with 10 sec and better cadence and with spectral resolution of 0.1 nm over most of the EUV range (6-105 nm). EVE's space weather data products are near realtime with latency less than a minute. While EVE Level 1-3 products are intended to be research quality, the quicklook Level 0C and 0CS products are appropriate for space weather operations. For example, the EVE Level 0CS product includes EVE's EUV SpectroPhometer (ESP) measurement of the 1-7 nm band irradiance that is used as a backup proxy for the GOES X-ray Sensor (XRS) 0.1-0.8 nm flare monitor. The ESP and also EVE's Solar Aspect Monitor (SAM) x-ray imager also provide realtime knowledge of the flare location. The EVE Level 0C product includes EVE's Multiple EUV Grating Spectrographs (MEGS) spectra and a listing of the brighter lines. Of particular interest for this session, the cooler coronal emission lines, e.g. Fe IX - Fe XII in the 17-20 nm range, often have coronal dimming during and after a flare, and the slope and depth of the dimming may be indicative of a coronal mass ejection (CME) velocity and mass. If so, then EVE's realtime monitor of these cooler coronal emissions could become a useful proxy for CME warnings.

Woods, T. N.; Woodraska, D.; Jones, A. R.; Eparvier, F. G.; Caspi, A.

2012-12-01

43

Red Tide  

NSDL National Science Digital Library

This CDC web page includes links to PDF or html formatted files containing information about Karenia brevis, a phytoplankton responsible for toxic red tide events. Links include information about red tide, what the CDC is doing about red tide, links to other red tide related sites, and publications about red tide.

Control, U. S.

44

Congruent responses to weather variability in high arctic herbivores  

PubMed Central

Assessing the role of weather in the dynamics of wildlife populations is a pressing task in the face of rapid environmental change. Rodents and ruminants are abundant herbivore species in most Arctic ecosystems, many of which are experiencing particularly rapid climate change. Their different life-history characteristics, with the exception of their trophic position, suggest that they should show different responses to environmental variation. Here we show that the only mammalian herbivores on the Arctic islands of Svalbard, reindeer (Rangifer tarandus) and sibling voles (Microtus levis), exhibit strong synchrony in population parameters. This synchrony is due to rain-on-snow events that cause ground ice and demonstrates that climate impacts can be similarly integrated and expressed in species with highly contrasting life histories. The finding suggests that responses of wildlife populations to climate variability and change might be more consistent in Polar regions than elsewhere owing to the strength of the climate impact and the simplicity of the ecosystem.

Stien, Audun; Ims, Rolf A.; Albon, Steve D.; Fuglei, Eva; Irvine, R. Justin; Ropstad, Erik; Halvorsen, Odd; Langvatn, Rolf; Loe, Leif Egil; Veiberg, Vebj?rn; Yoccoz, Nigel G.

2012-01-01

45

A Tide Climatology for Boston, Massachusetts.  

National Technical Information Service (NTIS)

The Techniques Development Laboratory in cooperation with the Boston Weather Service Forecast Office has compiled a climatology of measured tide levels for Boston, Mass. Approximately 44 years (January 1936 through March 1980) of hourly tide levels were u...

W. S. Richardson N. A. Pore D. M. Feit

1982-01-01

46

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

NASA Astrophysics Data System (ADS)

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- ?) 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 by nonlinear shear tidal stresses, acting as a 'tidal winds' on the surfaces. Harmonic analysis shows, that at least five harmonics should be taken in account: three semidiurnal M2, S2, N2 and two diurnal K1 and O1. We present results from the following experiments: (a) with tidal forcing and without tidal forcing; (b) with climatic runoff and with Dai and Trenberth database. To examine the effects of summer ice openings on the formation of brine rejection and dense water cascades, additional idealised experiments have been performed: (c) for initial conditions of hydrographic fields and fluxes for 1978 with initial summer ice concentration of 2000; (d) opposite case of initial ocean conditions for 2000 and ice concentration of 1978. The comparisons with global ORCA-025 simulations and available data are discussed.

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

2013-04-01

47

Weathering  

NSDL National Science Digital Library

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

Gore, Pamela

1995-08-29

48

Interannual variability characteristics and simulated crop response of four stochastic weather generators  

Microsoft Academic Search

Many stochastic weather generators commonly used with crop models tend to under predict interannual variability of climate and, as a result, distort distributions of crop simulation results. We examine the ability of four stochastic weather generators, WeatherMan, MARKSIM, WM2 and LARS-WG, to reproduce interannual variability of monthly climate and crop simulation results. Comparisons were based on bias and RMSE of

Theodoruos Mavromatis; James W Hansen

2001-01-01

49

Variability of the equatorial electrojet: Its relations to the Sq current system and semidiurnal tides  

SciTech Connect

Average diurnal and seasonal variations of the horizontal geomagnetic element {Delta}H are examined. The semiannual variation in equatorial electrojet strength is found to disappear in afternoon hours. This may be related to changes in the latitude of the Sq current system focus during the day. This in turn may be caused by a superposed semidiurnal tide and may also explain {Delta}H variations at stations near the focus.

Stening, R.J. (Univ. of New South Wales, Kensington (Australia))

1991-11-01

50

Graphing Tides  

NSDL National Science Digital Library

Student graphing of high and low tide from locations showing the three tide types (diurnal, semi-diurnal, and mixed) and the Bay of Fundy (tidal amplitude increased by resonance). Students recognize that not all tides are the same and that location is an important control on tides.

Farley, Martin

51

Ocean tides  

NASA Technical Reports Server (NTRS)

A review of recent developments in the study of ocean tides and related phenomena is presented. Topics briefly discussed include: the mechanism by which tidal dissipation occurs; continental shelf, marginal sea, and baroclinic tides; estimation of the amount of energy stored in the tide; the distribution of energy over the ocean; the resonant frequencies and Q factors of oceanic normal modes; the relationship of earth tides and ocean tides; and numerical global tidal models.

Hendershott, M. C.

1975-01-01

52

Weather  

NSDL National Science Digital Library

The National Oceanic and Atmospheric Administration (NOAA) provides these two Websites on weather. The first site serves as a major hub for information related to weather, with links to primary data sources, forecasts, maps, images (such as the latest satellite imagery for North America), and a wealth of other data, including space weather. Researchers will also find links to national weather research centers and other related agencies.

53

Weather  

NSDL National Science Digital Library

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

Jennie, Miss

2009-10-22

54

Physical mechanisms of solar variability influence on weather and climate  

Microsoft Academic Search

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;

Sergei Avakyan

2010-01-01

55

The impact of weather variability on British outbound flows  

Microsoft Academic Search

Climate can be understood both as a resource and a motivation for tourism. This study focuses on the second issue trying to\\u000a establish the sensitivity to weather anomalies of the outbound flows from United Kingdom, the third biggest international\\u000a tourist spender country. Using transfer function models it is possible to analyze the significance of the short-term weather\\u000a conditions in the

Jaume Rosselló-Nadal; Vivian Cárdenas

2011-01-01

56

Variability of winter storminess in the eastern United States during the 20th century from tide gauges  

NASA Astrophysics Data System (ADS)

An important impact of mean sea level change is the effect on extreme water levels caused by storms. When assessing this impact in a particular region, however, it is important to consider changes in the frequency of storms in addition to the effect of mean sea level change. Long-term variability of winter storminess in the eastern United States was studied using water level measurements from coastal tide gauges. The proximity to the coast of the primary winter storm track in the region allows the use of tide gauges to study temporal modulations in the frequency of these storms. The primary result is a significant multidecadal increase in the number of storms affecting the southeastern United States from the early to late 20th century. This change would not be detected in analyses of meteorological products limited to the latter half of the century. We propose this change is due to an increased tendency for the jet stream to mender south over the eastern United States since the 1950s. This mechanism is supported by long-term changes in the large-scale sea level pressure pattern over North America.

Thompson, P. R.; Mitchum, G. T.; Vonesch, C.; Li, J.

2012-12-01

57

Seasonal variability and north-south asymmetry of internal tides in the deep basin west of the Luzon Strait  

NASA Astrophysics Data System (ADS)

Temporal and spatial variability of internal tides (ITs) in the deep basin west of the Luzon Strait were examined, based on two 9-month mooring current observations from autumn 2008 to summer 2009. The baroclinic current measurements exhibited north-south asymmetry and temporal variation. At the southern site (19.5°N), the kinetic energy of diurnal IT was dominant over that of semidiurnal IT by a factor of 3 to 4, whereas at the northern site (~ 21°N), the diurnal energy was comparable to or a little larger than semidiurnal energy. At both sites, the motions of semidiurnal IT were recognized as seasonally invariant, while diurnal IT showed notable seasonal variation, namely, stronger in summer and winter but weaker in spring and autumn. The seasonal variation was mainly modulated by the astronomical tides in the Luzon Strait rather than by the seasonal thermocline. Both diurnal and semidiurnal ITs contained stronger coherent signals than incoherent counterparts at two sites, but the IT at the southern site was more coherent than that at the northern site. Diurnal IT is more coherent than the semidiurnal IT at each site. The spatial-temporal variations were probably due to IT interferences from various sources within the Luzon Strait and modulation by varying background conditions.

Xu, Zhenhua; Yin, Baoshu; Hou, Yijun; Liu, Antony K.

2014-06-01

58

Weather  

NSDL National Science Digital Library

You will learn how to describe and observe changes in weather patterns by completing the following activities. The students will record and report changes in weather on their data sheet. The Process: Read the information on How Air Pressure Affects You. In this article you will see the term barometer. Write its definition. Now look over Weather Facts. Now go to Investigate Climate Conditions and use the weather maker to observe the effects of certain changes. Answer the questions: How much of a change in temperature is needed to make it ...

Lauren, Ms.

2010-11-17

59

Variability of the Ionospheric WN4 Structure and the Causative DE3 Tide  

NASA Astrophysics Data System (ADS)

It is suggested that the longitudinal wavenumber-4 (WN4) structure in the ionospheric F-region is caused by the non-migrating tidal mode DE3 (diurnal eastward wavenumber-3) in the upper atmosphere at the ionospheric E region altitudes. In order to investigate the relationships existing in these two kind waves, we first deduce the WN4 structure from the latitudinally integration of total electron content (ITEC), which is retrieved from the JPL GIMs. Meanwhile, we use the upper atmospheric observation of SEBER and TIDI on board the TIMED satellite to obtain the temperature (T), the zonal and meridional wind (U, V) components of DE3 tide. It is found that both the intra-and inter-annual variations WN4 is much similar to the T and U components of DE3, while it is quite different to the V component. The intra-annual variation of WN4 and DE3-T/U is mainly acted as that both waves present chiefly in two periods of a year, they appear in later spring with moderate strength, and become very strong in summer and autumn seasons. In contrast, both waves are very weak or tend to vanish during winter. The inter-annual variation of WN4/DE3 waves are represented as the quasi-biennial oscillation (QBO). Both them are stronger during the eastward QBO wind phase than during the westward wind phase. The similar intra-and inter-annual variations of the WN4 and DE3-T/U waves provide a signify evidence that the ionospheric longitudinal WN4 structure is excite by the upper atmospheric non-migration tide DE3.

Wan, Weixing; Xiong, Jiangang; Ren, Zhipeng; Liu, Libo; Zhang, Manlian; Ding, Feng; Ning, Baiqi

60

Earth Tides.  

National Technical Information Service (NTIS)

The report explains that the effects of ocean tides on Earth tide observations can best be observed by a network of stations, varying in distance to the coast, which systematically monitor the ocean loading or attraction contributions to the observations....

B. D. Zetler J. T. Kus

1971-01-01

61

Analyzing the impact of weather variables on monthly electricity demand  

Microsoft Academic Search

The electricity industry is significantly affected by weather conditions both in terms of the operation of the network infrastructure and electricity consumption. Following privatization and deregulation, the electricity industry in the U.K. has become fragmented and central planning has largely disappeared. In order to maximize profits, the margin of supply has decreased and the network is being run closer to

Ching-Lai Hor; Simon J. Watson; Shanti Majithia

2005-01-01

62

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

Microsoft Academic Search

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

Marc B. Parlange; Richard W. Katz

2000-01-01

63

Weather.  

ERIC Educational Resources Information Center

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)

Web Feet K-8, 2000

2000-01-01

64

Weathering  

Microsoft Academic Search

In the natural environment, weathering and breakdown of stone is an accepted part of long-term landscape development but the\\u000a same acceptance of change and deterioration is not extended to stone used in construction especially when such deterioration\\u000a affects historically and\\/or culturally important structures. The value of an integrative approach to improve understanding\\u000a of weathering and failure of building stone is

P. A. Warke; J. McKinley; B. J. Smith

65

Weathering of plagioclase across variable flow and solute transport regimes  

NASA Astrophysics Data System (ADS)

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 various field studies. In this study, it is suggested that part of the apparent discrepancy between the results is due to changes in hydraulic diffusivity of the weathering environments occurring over the geologic times.

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

2012-02-01

66

Physical mechanisms of solar variability influence on weather and climate  

NASA Astrophysics Data System (ADS)

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 the ionospheric microwave radiation and in realization of the dissociative recombination of cluster ions in troposphere. The mechanism enables agents of solar and geomagnetic activities affect atmospheric processes with help the flux of microwaves from ionosphere. This first agent under consideration is variation of fluxes of solar EUV and X -ray radiation during flares. The second agent is fluxes of electrons and protons which precipitate from radiation belts as a result of geomagnetic storms.. Our novel radiooptical trigger mechanism of influence of solar and geomagnetic activity on the formation of weather and climate changes consists of three stages. The first stage is an increase in generation of the microwave radiation which penetrates from the ionosphere to the earth surface. The microwave radiation arises from the transitions between Rydberg states which are exited by the energetic ionospheric electrons namely photoelectrons, secondary electrons and Auger electrons. The second stage is a change in the proportion of water vapour to water clusters caused by increased microwave radiation. The third stage is a change of the atmosphere transparence in the absorption bands of water vapour and clusters and appearance of optically-thin clouds at high and middle altitudes. These clouds cause a net warming due to their relative transparency at short wavelengths but opacity in the IR region The atmosphere transparence determines the fluxes of solar irradiance coming down as well as flux of the thermal radiation coming out from the underlying surface. We emphasize that all stages of the proposed mechanism are experimentally confirmed: the microwave ionospheric emission, which intensifies during solar and magnetic storms, was detected; the regulation of humidity at altitude higher than 2 km by the solar microwave emission and during of solar flares was registered; a direct influence of solar flares and magnetic storms on the total cloudiness is distinctly registered at least in some geographic areas.

Avakyan, Sergei

2010-05-01

67

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

SciTech Connect

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.

Royer, T.C. (Univ. of Alaska, Fairbanks (United States))

1993-03-15

68

Earth tides  

SciTech Connect

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.

Harrison, J.C.

1984-01-01

69

A method of land evaluation including year to year weather variability  

Microsoft Academic Search

Land evaluation is sensitive to the effects of annual variability in weather. A method to incorporate this variability into land evaluation systems is proposed, using the land capability system for Scotland as a case study. Land capability classes were found to be sensitive to the climate reference period from which data are taken. Individual stations rarely occupy their long-term land

Gordon Hudson; Richard V. Birnie

2000-01-01

70

Lunar Tides  

NSDL National Science Digital Library

This site explains the relationship between our tides on Earth and the Moon. Differential forces are explained as a function of distance from various points on Earth to the Moon. The site explains both a simple tidal model with a smooth water covered Earth and a more realistic tidal model that takes into account the earth-moon system and friction. This site also explains spring tides and neap tides and also tidal coupling and gravitational locking.

2007-03-04

71

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)

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.

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

2014-08-01

72

Perspectives of non-gaussianity in large scale weather and climate Variability  

NASA Astrophysics Data System (ADS)

Understanding non-Gaussian statistics of weather and climate variability has important consequences in the atmospheric and ocean sciences not least because weather and climate risk assessment depends on knowing and understanding the exact shape of the system's probability density function. While there is no doubt that many atmospheric variables exhibit non-Gaussian statistics on many time (and spatial) scales a full and complete understanding of this phenomenon remains a challenge. Various mechanisms behind the observed non-Gaussian statistics have been proposed but remain, however, multifaceted and scattered in the literature. Given the importance of this subject for climate research, and in an attempt to contribute to this topic a thorough review and discussion of the different mechanisms that lead to non-Gaussian weather and climate variability are presented in this paper and an outlook is given.

Hannachi, Abdel; Sura, Philip

2014-05-01

73

Red Tides  

NSDL National Science Digital Library

This comprehensive website answers questions such as: what is red tide, where are they found, why do they occur, how do they affect marine organisms, how do they affect humans, how are shellfish tested for the toxin, and what is being done to remediate the red tide problem. The site features color pictures and black and white maps.

Communications Directorate, Department O.

74

Earth tides  

Microsoft Academic Search

The main geometrical characteristics and mechanical properties of bodily tides are described, using the convenient elastic parameters of Love. The problem of the Earth's deformation is a problem of spherical elasticity of the sixth order. The importance of Earth tides in astronomy and geophysics is emphasized by their relation to the precession-nutation and tesseral tidal problems, the secular retardation of

Paul Melchior

1974-01-01

75

Weather  

NSDL National Science Digital Library

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

Caitlin, Ms.

2009-10-21

76

Global structure and seasonal and interannual variability of the migrating diurnal tide seen in the SABER\\/TIMED temperatures between 20 and 120 km  

Microsoft Academic Search

The present paper is focused on the global spatial (altitude and latitude) structure and seasonal and interannual variability of the migrating diurnal tide derived from the Sounding of the Atmosphere using Broadband Emission Radiometry\\/Thermosphere-Ionosphere-Mesosphere-Energetics and Dynamics (SABER\\/TIMED) temperature measurements for 6 full years (January 2002 to December 2007). The tidal results are obtained by a new analysis method where the

P. Mukhtarov; D. Pancheva; B. Andonov

2009-01-01

77

Daily weather variables and affective disorder admissions to psychiatric hospitals  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

78

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

NASA Technical Reports Server (NTRS)

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.

Choudhury, B. J.

1982-01-01

79

Low-Frequency Pycnocline Depth Variability at Ocean Weather Station P in the Northeast Pacific  

Microsoft Academic Search

Low-frequency variability of the depth of the main pycnocline at Ocean Weather Station P and over the northeast Pacific is examined in terms of the one-dimensional response to local Ekman pumping according to the Hasselmann stochastic climate model. The model is forced with monthly wind stress curl anomalies derived from the National Centers for Environmental Prediction reanalysis for the period

Patrick F. Cummins; Gary S. E. Lagerloef

2002-01-01

80

Electricity load forecasting based on weather variables and seasonalities: A neural network approach  

Microsoft Academic Search

Three models are presented to forecast electricity load based on weather variables, represented by heating degree days (HDD) and cooling degree days (CDD), and weekly and monthly seasonalities, expressed by the day of the week, a holiday, and the month of the year. The first model is a classical linear regression model that serves as a benchmark for this study.

R. S. Elias; Liping Fang; M. I. M. Wahab

2011-01-01

81

Guidelines for the Use of Variable Speed Limit Systems in Wet Weather: FHWA Safety Program.  

National Technical Information Service (NTIS)

This report provides guidance on the use of variable speed limit (VSL) systems in wet weather at locations where the operating speed exceeds the design speed and the stopping distance exceeds the available sight distance. The use of VSLs during inclement ...

B. Katz B. Kuhn D. Warren J. Atkinson K. Baike K. Donoughe M. Finley

2012-01-01

82

Nonmigrating tides  

NASA Technical Reports Server (NTRS)

Recently an interesting advancement in the study of nonmigrating tides has occurred. There have been two distinct approaches in works on this subject. One is based on mechanistic models as considering nonuniform global distribution of water vapor or heating only on land, solving a set of linear equations. It is found that insolation absorption of the nonuniformly distributed water vapor produces only weak nonmigrating tides in the lower thermosphere; the planetary boundary layer heating on land can explain the enhanced tides on land and those with short vertical wavelengths in the stratosphere. The other approach is novel and uses simulation on the general circulation model (GCM). This realistic model can reproduce tides globally and in many details. The enhancement of two nonmigrating modes as eastward traveling modes with a wave number 3 and westward traveling modes with a wave number 5 is in surprisingly good agreement with observation at sea level, at 700 mb and even at 300 mb.

Kato, S.

1989-01-01

83

Seasonality and weather-driven variability of transpacific transport  

NASA Astrophysics Data System (ADS)

We quantify transport from the industrialized regions of E Asia using the transit-time probability density function, ��, to isolate the role of transport from any other factors, such as chemistry and deposition. Using the offline transport model MATCH driven by NCEP reanalyses, we calculate ��, which is the mass fraction of air that had its last contact with the E-Asian source region during a given day, for each day of a three-year period. Ensemble means of �� establish the climatological seasonal-mean transport from E Asia. Export from the source region is most efficient in spring, with nearly all E-Asian air involved in transpacific transport. In summer, E-Asian air is transported aloft across the Pacific and, in nearly equal measure, west over SE Asia to the Middle East. Winter transport is similar to that of spring, except winter has low-level transport to SE Asia. Fall transport is intermediate between that of summer and winter. For all seasons, the most probable transit times to N America are 6-8 days in the mid-to-upper troposphere and approximately one week (two for summer) longer at the surface. The surface signal of E-Asian air over N America is strongest in spring. Daily variability of transpacific transport is quantified in terms of the transit-time partitioned burden of E-Asian air over western N America. The standard deviation of the transit-time partitioned fluctuations has a nearly universal dependence on the corresponding seasonal-mean burden. The standard deviation peaks several days before the burden at a transit time of ˜7 days. Lagged event and nonevent composites, based on the western N-American burden of E-Asian air, reveal that transport events are associated with dipolar wind perturbations over the eastern Pacific that are positioned and phased to receive enhanced Asian outflow. Surface-pressure correlations are consistent with an associated strengthened Pacific High and weakened Aleutian Low.

Holzer, Mark; Hall, Timothy M.; Stull, Roland B.

2005-12-01

84

Weather variability permitted within amphibian monitoring protocol and affects on calling Hylidae.  

PubMed

Anuran populations are sensitive to changing environmental conditions and act as useful indicators. Presently, much information collected concerning frog populations comes from volunteers following the North American Amphibian Monitoring Protocol. Does weather variability allowed within protocol affect the abundance of calling frogs? For 10 years, Credit Valley Conservation (Ontario, Canada) has been collecting anuran data concerning nine frog species employing three frog monitoring runs. Records include frog abundance by protocol code and five weather variables. Antecedent precipitation and temperature were determined from the nearest weather station. Locations with large source populations of two Hylidae species were selected (spring peeper calling in April and gray tree frog in May). Spearman correlations suggested there were no significant relationships between calling abundance of Hylidae species and ambient wind speed or humidity. However, gray tree frogs were temperature sensitive and calling was significantly related to increased water and air temperatures as well as day time high temperatures over the previous 2 weeks. Both species of calling Hylidae were affected by the volume and timing of precipitation (though, in different ways). Gray tree frogs seem to prefer drier conditions (when temperatures are significantly warmer) while spring peepers prefer to call during, or closely following, precipitation. Monitors targeting gray tree frog should track local weather conditions and focus on evenings when it is (a) warmer than the minimum temperatures and (b) drier than suggested by the protocol. It is recommended that an additional monitoring run could be added to reduce detection variability of this species. PMID:23625355

Milne, Robert; Bennett, Lorne; Hoyle, Mathew

2013-11-01

85

Toxic Tide  

NSDL National Science Digital Library

This website provides access to a news article published in September 2005 by the Sarasota Herald-Tribune in which Mote Marine researchers responded to a series of questions posed by the Herald-Tribune editorial board about red tides. The article discusses a historical bloom event that occurred on Florida's Gulf Coast in 2005. The article also provides information about the causative organism, Karenia brevis, as well as about the general occurrence of red tides in this region, health effects, and the environmental factors that trigger a bloom event.

Mahadevan, Kumar; Pierce, Richard; Kirkpatrick, Barbara; Kirkpatrick, Gary; Dixon, L. K.; Herald-Tribune, Sarasota

86

Tides and Water Levels: What are Tides?  

NSDL National Science Digital Library

This tutorial is an overview of the complex systems that govern the movement of tides and water levels. The tutorial is content rich and presented in easy-to-understand language with many illustrative and interactive graphics to visually enhance the text. This page begins with what tides are while other linked pages cover What Causes Tides, Gravity, Inertia, and Bulges, Changing Angles and Tides, The Frequency of Tides, Tidal Variations, Types and Causes of Tidal Cycles, What Else Affects Tides, Monitoring the Tides, How are Tides Measured, and a page of references.

87

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

NASA Technical Reports Server (NTRS)

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

Roberts, J. Brent; Clayson, Carol Anne

2013-01-01

88

Kingdom of the Tides.  

ERIC Educational Resources Information Center

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…

Carter, Samuel, III

89

The impact of local geochemical variability on quantifying hillslope soil production and chemical weathering  

NASA Astrophysics Data System (ADS)

Soil-mantled upland landscapes are widespread across the habitable world, support extensive life, and are the interface between the atmosphere, hydrosphere, and lithosphere but typically are not cultivated. Soil found across such landscapes fits the conceptual framework of a physically mobile layer derived from the underlying parent material along with some locally derived organic content. The extent and persistence of these upland soils depend on the long-term balance between soil production and erosion. Here we briefly review methods used to quantify the physical and chemical processes of soil production and erosion and revisit three granitic study areas in southeastern Australia and northern California that enabled early quantification of the soil production function and topographic controls on chemical weathering. We then present new major and trace element data from 2-m by 2-m pits dug at each field site to quantify local variability of Zr concentrations and the chemical index of alteration (CIA), weathering indices used to determine chemical weathering rates and extents in soils and saprolites. Using both new and previously published data, we compare differences between local variability and regional, as well as intersite variability of these important indices. For each of the 2-m pits, we collected 25 samples and found that the simple mean and the 2? standard deviation best describe the local variation in the data. We also find that the variability in the 2-m pit data lies within variability observed in the same data from samples collected in individual soil pits across each of the field sites and that the differences between sites are consistent with previously published results. These observations highlight the importance of quantifying local scale variability in studies that use similar, multifaceted measurements to quantify hillslope soil production and erosion processes.

Heimsath, Arjun M.; Burke, Benjamin C.

2013-10-01

90

WEATHER RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY CONTROLLED ENVIRONMENT  

SciTech Connect

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.

CAMERON, M.A.

2007-04-16

91

WEATHER RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY CONTROLLED ENVIRONMENT  

SciTech Connect

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.

CAMERON, M.A.

2007-04-16

92

Interpreting and analyzing King Tide in Tuvalu  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

93

Short-term variability and summer-2009 averages of the mean wind and tides in the mesosphere and lower thermosphere over Langfang, China (39.4°N, 116.7°E)  

NASA Astrophysics Data System (ADS)

Data obtained from the newly installed MF radar at Langfang (39.4°N, 116.7°E), China, during the summer months of 2009 are used to study the short-term variability and summer averages of the mean wind and tidal oscillations in the mesosphere and lower thermosphere (MLT). Both the zonal and meridional daily winds between 80 km and 98 km show considerable day-to-day variability; their Lomb-Scargle spectra reveal active quasi-2-day and quasi-16-day planetary waves. The tidal large day-to-day variations have time scales of days or longer, which could be attributed to the contribution of planetary waves. The summer-averaged zonal wind is westward below 82 km and eastward above 88 km with the transition altitude at ˜85 km. The meridional wind is dominated by the southward wind. The summer-averaged zonal and meridional semidiurnal tides exhibit amplitudes of 10-15 m/s; they are larger than the diurnal tides, whose amplitudes are 5-10 m/s. The phase tilt of the semidiurnal tide is downward, indicating this component is excited below the MLT. For the diurnal tide, the phase propagation is downward above 86 km but it is upward below 86 km, which indicates that the tide is evanescent or a mixture of evanescent and propagating modes. These wind and tide observations are compared with data from other mid-latitude stations at ˜40°N and with the HWM and GSWM models. Comparisons show that HWM-93 is better than HWM-07 in delineating the 2009 summer-averaged zonal wind over Langfang while both have systematic discrepancy in delineating the meridional mean winds. The prediction of the 2009 summer-averaged diurnal tide over Langfang by GSWM-09 is better than that from GSWM-02 but not the semidiurnal tide.

Xiao, Cunying; Hu, Xiong; Smith, Anne K.; Xu, Qingchen; Chen, Xuxing

2013-01-01

94

Using Space Weather Variability in Evaluation the Radiation Environment Specifications for NASA's Constellation Program  

NASA Technical Reports Server (NTRS)

Hardware design environments for NASA's Constellation Program-the Vision for Space Exploration program to design and build new vehicles for servicing low Earth orbit and the Moon and beyond-have been developed that are necessarily conservative in nature to assure robust hardware design and development required to build space systems which will meet operational goals in a wide range of space environments, This presentation will describe the rationale used to establish the space radiation and plasma design environments specified for a variety of applications including total ionizing radiation dose, dose rate effects, and spacecraft charging and will compare the design environments with "space weather" variability to evaluate the applicability of the design environments and potential vulnerabilities of the system to extreme space weather events.

Coffey, Victoria N.; Minow, Joseph I.; Bruce, Margaret; Howard, James W.

2008-01-01

95

Virtual Tide Pool  

NSDL National Science Digital Library

Virtual Tide Pool features a three dimensional view of a tide pool during both low and high tides. Students can see animals that live under, above, and at the waters surface. This site offers the ability to pan the tide pool for a 360 degree view, with zoom options, and gives descriptions of the animals found during both low and high tides.

Science NetLinks (PBS;)

2003-04-29

96

Neural Substrates Associated with Weather-Induced Mood Variability: An Exploratory Study Using ASL Perfusion fMRI  

PubMed Central

Daily variations in weather are known to be associated with variations in mood. However, little is known about the specific brain regions that instantiate weather-related mood changes. We used a data-driven approach and ASL perfusion fMRI to assess the neural substrates associated with weather-induced mood variability. The data-driven approach was conducted with mood ratings under various weather conditions (N = 464). Forward stepwise regression was conducted to develop a statistical model of mood as a function of weather conditions. The model results were used to calculate the mood-relevant weather index which served as the covariate in the regression analysis of the resting CBF (N = 42) measured by ASL perfusion fMRI under various weather conditions. The resting CBF activities in the left insula-prefrontal cortex and left superior parietal lobe were negatively correlated (corrected p<0.05) with the weather index, indicating that better mood-relevant weather conditions were associated with lower CBF in these regions within the brain’s emotional network. The present study represents a first step toward the investigation of the effect of natural environment on baseline human brain function, and suggests the feasibility of ASL perfusion fMRI for such study.

Gillihan, Seth J.; Detre, John A.; Farah, Martha J.; Rao, Hengyi

2013-01-01

97

The ``Mars-Sun Connection" and the Impact of Solar Variability on Mars Weather and Climate  

NASA Astrophysics Data System (ADS)

We develop the scientific case to measure simultaneously the UV and near-UV solar irradiance incident on the Mars atmosphere and at the Martian surface, to explore the effects and influence of Solar variability and ``Space Weather" on Mars weather and climate, its implications for life, and the implications for astronaut safety on future manned Mars missions. The UV flux at the Martian surface is expected to be highly variable, due to diurnal, daily, and seasonal variations in opacity of atmospheric dust and clouds, as well as diurnal and seasonal variations in ozone, water vapor and other absorbing species. This flux has been modeled (Kuhn and Atreya, 1979), but never measured directly from the Martian surface. By directly observing the UV and near UV solar irradiance both at the top of the atmosphere and at the Martian surface we will be able to directly constrain important model parameters necessary to understand the variations of atmospheric dynamics which drive both Mars weather and climate. Directly measuring the solar UV radiation incident upon the Mars atmosphere and at the Martian surface also has important implications for astronaut safety on future manned Mars missions. The flux at the surface of Mars at 250 nm is also believed to be approximately 3000 times greater than that on Earth. This presents potential hazards to future human explorers as well as challenges for future agriculture such as may be carried out in surface greenhouses to provide food for human colonists. A better understanding of the surface flux will aid in designing appropriate protection against these hazards.

Hassler, D. M.; Grinspoon, D. H.

2003-05-01

98

The "Mars-Sun Connection" and the Impact of Solar Variability on Mars Weather and Climate  

NASA Astrophysics Data System (ADS)

We develop the scientific case to measure simultaneously the UV and near-UV solar irradiance incident on the Mars atmosphere and at the Martian surface, to explore the effects and influence of Solar variability and "Space Weather" on Mars weather and climate, its implications for life, and the implications for astronaut safety on future manned Mars missions. The UV flux at the Martian surface is expected to be highly variable, due to diurnal, daily, and seasonal variations in opacity of atmospheric dust and clouds, as well as diurnal and seasonal variations in ozone, water vapor and other absorbing species. This flux has been modeled (Kuhn and Atreya, 1979), but never measured directly from the Martian surface. By directly observing the UV and near UV solar irradiance both at the top of the atmosphere and at the Martian surface we will be able to directly constrain important model parameters necessary to understand the variations of atmospheric dynamics which drive both Mars weather and climate. Directly measuring the solar UV radiation incident upon the Mars atmosphere and at the Martian surface also has important implications for astronaut safety on future manned Mars missions. The flux at the surface of Mars at 250 nm is also believed to be approximately 3000 times greater than that on Earth. This presents potential hazards to future human explorers as well as challenges for future agriculture such as may be carried out in surface greenhouses to provide food for human colonists. A better understanding of the surface flux will aid in designing appropriate protection against these hazards.

Hassler, D. M.; Grinspoon, D.

2004-05-01

99

Influence of seasonal weather and climate variability on crop yields in Scotland  

NASA Astrophysics Data System (ADS)

The climatic sensitivity of four important agriculture crops (wheat, barley, oats, potatoes) in a northern temperate bioclimatic region is investigated using national-level yield data for 1963-2005. The climate variables include monthly and annual meteorological data, derived bioclimatic metrics, and the North Atlantic Oscillation index. Statistical analysis shows that significant relationships between yield and climate vary depending on the crop type and month but highlight the influence of precipitation (negative correlation) and sunshine duration (positive correlation) rather than temperature. Soil moisture deficit is shown to be a particular useful indicator of yield with drier summers providing the best yields for Scotland as a whole. It is also tentatively inferred that the sensitivity of these crops, particularly wheat and barley, to soil moisture deficits has increased in recent years. This suggests that improved crop yields are optimised for dry sunny years despite the continued prevalence of considerable inter-annual variability in seasonal weather.

Brown, Iain

2013-07-01

100

Bodily Tides  

NASA Astrophysics Data System (ADS)

The equilibrium tide model in the weak friction approximation is used by the binary star and exoplanet communities to study the tidal evolution of short-period systems. However, each uses a slightly different approach which potentially leads to different conclusions about the timescales on which various processes occur. Here we present an overview of these two approaches, and show that for short-period planets the circularization timescales they predict differ by at most a factor of a few. A discussion of the timescales for orbital decay, spin-orbit synchronization and spin-oribt alignment is also presented.

Mardling, Rosemary. A.

2011-02-01

101

Tides and gravity labs  

NSDL National Science Digital Library

How does gravity cause tides in the oceans? This section, part of an interactive laboratory series for grades 8-12, introduces students to four activities on tides and gravity that cover critical orbital speed between Earth and the moon, gravitational forces between two bodies, tidal effects from the sun and moon, and the change in tidal levels over time. The activities include hands-on animations of concepts whose variables can be manipulated by students. Questions posed to students include answer boxes that are printable upon conclusion of the activities. The final activity involves collecting tidal data over 24-hour and 29-day periods. Student data are stored in printable tables. Views of moon phases for each time period are provided, as is a downloadable worksheet. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2002-01-01

102

Influence of synoptic weather patterns on solar irradiance variability in Europe  

NASA Astrophysics Data System (ADS)

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 poorly represented by the GWL models, but in northern Europe, the GWL model recreates observed decadal solar variability well. This finding suggests that natural and/or anthropogenic variations in circulation patterns have influenced solar dimming and brightening to a higher degree in the north than in the rest of Europe.

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

2014-05-01

103

Relative Roles of Weather Variables and Change in Human Population in Malaria: Comparison over Different States of India  

PubMed Central

Background Pro-active and effective control as well as quantitative assessment of impact of climate change on malaria requires identification of the major drivers of the epidemic. Malaria depends on vector abundance which, in turn, depends on a combination of weather variables. However, there remain several gaps in our understanding and assessment of malaria in a changing climate. Most of the studies have considered weekly or even monthly mean values of weather variables, while the malaria vector is sensitive to daily variations. Secondly, rarely all the relevant meteorological variables have been considered together. An important question is the relative roles of weather variables (vector abundance) and change in host (human) population, in the change in disease load. Method We consider the 28 states of India, characterized by diverse climatic zones and changing population as well as complex variability in malaria, as a natural test bed. An annual vector load for each of the 28 states is defined based on the number of vector genesis days computed using daily values of temperature, rainfall and humidity from NCEP daily Reanalysis; a prediction of potential malaria load is defined by taking into consideration changes in the human population and compared with the reported number of malaria cases. Results For most states, the number of malaria cases is very well correlated with the vector load calculated with the combined conditions of daily values of temperature, rainfall and humidity; no single weather variable has any significant association with the observed disease prevalence. Conclusion The association between vector-load and daily values of weather variables is robust and holds for different climatic regions (states of India). Thus use of all the three weather variables provides a reliable means of pro-active and efficient vector sanitation and control as well as assessment of impact of climate change on malaria.

Goswami, Prashant; Murty, Upadhayula Suryanarayana; Mutheneni, Srinivasa Rao; Krishnan, Swathi Trithala

2014-01-01

104

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

PubMed Central

A study was conducted to evaluate the influence of weather (precipitation and temperature) and plant communities on grasshopper density over a 14-year period (1996–2009) in Benito Juárez County, Southern Pampas, Argentina. Total density strongly varied among plant communities. Highest values were registered in 2001 and 2003 in highly disturbed pastures and in 2002 and 2009 in halophilous grasslands. Native grasslands had the lowest density values. Seasonal precipitation and temperature had no significant effect on total grasshopper density. Dichroplus elongatus (Giglio-Tos) (Orthoptera: Acridoidea), Covasacris pallidinota (Bruner), Dichroplus pratensis Bruner, Scotussa lemniscata Stål, Borellia bruneri (Rehn) and Dichroplus maculipennis (Blanchard) comprised, on average, 64% of the grasshopper assemblages during low density years and 79% during high density years. Dichroplus elongatus, S. lemniscata and C. pallidinota were the most abundant species in 2001, 2002 and 2003, while D. elongatus, B. brunneri and C. pallidinota in 2009. Dichroplus elongatus and D. pratensis, mixed feeders species, were positively affected by summer rainfall. This suggests that the increase in summer precipitation had a positive effect on the quantity and quality forage production, affecting these grasshopper populations. Scotussa lemniscata and C. pallidinota were negatively affected by winter and fall temperature, possibly affecting the embryonic development before diapause and hatching. Dichroplus elongatus and D. pratensis were associated with highly disturbed pastures, S. lemniscata with pastures and B. bruneri and D. maculipennis with halophilous grasslands. Covasacris pallidinota was closely associated with halophilous grasslands and moderately disturbed pastures. Weather conditions changed over the years, with 2001, 2002 and 2003 having excessive rainfall while 2008 and 2009 were the driest years since the study started. We suggest that although seasonal precipitation and temperature had no significant effect on total grasshopper density, these weather variables and plant communities had differential influence on the dominant grasshopper species.

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

2011-01-01

105

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

PubMed

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

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

2006-05-01

106

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

NASA Astrophysics Data System (ADS)

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.

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

2006-05-01

107

Predicting trauma admissions: the effect of weather, weekday, and other variables.  

PubMed

One of the challenges all hospitals, especially designated trauma centers, face is how to make sure they have adequate staffing on various days of the week and at various times of the year. A number of studies have explored whether factors such as weather, temporal variation, holidays, and events that draw mass gatherings may be useful for predicting patient volume. This article looks at the effects of weather, mass gatherings, and calendar variables on daily trauma admissions at the three Level I trauma hospitals in the Minneapolis-St. Paul metropolitan area. Using ARIMA statistical modeling, we found that weekends, summer, lack of rain, and snowfall were all predictive of daily trauma admissions; holidays and mass gatherings such as sporting events were not. The forecasting model was successful in reflecting the pattern of trauma admissions; however, it's usefulness was limited in that the predicted range of daily trauma admissions was much narrower than the observed number of admissions. Nonetheless, the observed pattern of increased admission in the summer months and year-round on Saturdays should be helpful in resource planning. PMID:20069999

Friede, Kevin A; Osborne, Marc C; Erickson, Darin J; Roesler, Jon S; Azam, Arsalan; Croston, J Kevin; McGonigal, Michael D; Ney, Arthur L

2009-11-01

108

Global Interaction between Earth and Sea Tides  

Microsoft Academic Search

The vertical component of gravitational acceleration arising from the global M2 ocean tide is estimated by a numerical solution of hydrodynamic equations in a 4 ø grid system. Spherical harmonic series expansion and numerical integration results are discussed. Cor- responding perturbations of gravimetric factorand phase lag 0 at several earth tide sta- tions are given. High variability of corresponding corrections

E. Groten; J. Brennecke

1973-01-01

109

Spatial and temporal variability of extreme weather in the United States  

NASA Astrophysics Data System (ADS)

As the global climate is influenced by increased warming, the frequency of climate extremes will likely become more variable. The United States Historical Climate Network (USHCN) station data from 1900-2011 is used to quantify trends in daily extreme heat events, daily extreme cold events, and extreme daily precipitation within the contiguous United States. Climate data was spatially aggregated into respective Koeppen-Geiger climate zones where the 3 main zones are; arid, warm temperate and snow. Results show a gain or loss of 20 extreme temperature events and a gain or loss of 4 extreme precipitation events. The arid zone exhibited a loss of extreme minimum temperature a gain of extreme maximum temperature and a mixed result for extreme precipitation. The warm temperate zone indicated that the eastern region follows the exact same temperature trends as the arid zone but exhibits an overall loss of extreme precipitation. The western portion of the warm temperate zone exhibits a loss in extreme temperature events, a gain in extreme minimum temperature events and a gain in extreme precipitation. The trends in the snow zone reveal a mixed signal for extreme maximum temperature, a decline in extreme minimum temperature and a gain in extreme precipitation. Paired t-test results indicate statistically significant shifts in the magnitude of extreme weather events in each of the 3 main climate zones (arid, warm temperate and snow). This spatiotemporal analysis highlights how daily trends in extreme heat, extreme cold, and extreme precipitation have changed in the last 100 years in the context of specific climate zones. In order to understand the impact regional climate has on extreme events, trends in teleconnection patterns were examined in conjunction to daily weather. Teleconnection patterns that directly impact US weather are El Nino Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). The use of wavelet analysis, including the continuous wavelet transform, the wavelet cross wavelet transform and the wavelet transform coherence provide insight into the timescales of influence from ENSO and PDO on extreme weather events. The power spectra results from each wavelet analysis have been averaged across Koeppen-Geiger zone. Results indicate that extreme precipitation events have significantly different power spectras than normal events across all timescales. Specific patterns at the annual scale and shorter are found the arid zone for extreme maximum temperature, where results for minimum temperature trends vary.

Wilson, Cassandra Jo

110

The effect of weather variability on pediatric asthma admissions in Athens, Greece.  

PubMed

The aim of this study was to determine whether there is any association between weather variability and asthma admissions among children in Athens, Greece. Medical data were obtained from hospital registries of the three main Children's Hospitals in Athens during the 1978-2000 period; children were classified into two age groups: 0-4 and 5-14 years. The application of Generalized Linear Models with Poisson distribution revealed a significant relationship among asthma hospitalizations and the investigated parameters, especially for the children aged 0-4 years. Our findings showed that Hospital admissions for childhood asthma in Athens, Greece, is negatively correlated with discomfort index, air temperature and absolute humidity whereas there is a positive correlation with cooling power, relative humidity and wind speed. PMID:18259997

Nastos, Panagiotis T; Paliatsos, Athanasios G; Papadopoulos, Marios; Bakoula, Chryssa; Priftis, Kostas N

2008-01-01

111

The origin of tides  

NSDL National Science Digital Library

This QuickTime animation points out how the pull of gravity results in the tides. A high tide results on the near side of the Earth-moon alignment. The bulge on the opposite side results as the solid earth is pulled away from water on its far side where the moon�s gravitational pull is weakest. These two high tide bulges stay in place as the earth rotates, leading to two high tides and two low tides every day.

Mcgraw-Hill

112

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

113

Temporal Variability of Fair-Weather Cumulus Statistics at the ACRF SGP Site  

SciTech Connect

Continental fair-weather cumuli exhibit significant diurnal, day-to-day, and year-to-year variability. This study describes the climatology of cloud macroscale properties, including the cloud-base height, cloud-top height, cloud thickness, and cloud chord length over the U.S. Department of Energy¹s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ARCF) Southern Great Plains (SGP) site. The diurnal cycle of cloud fraction, cloud-base height, and cloud-thickness were well defined. The cloud fraction reached its maximum value near 14:00 CST. The average cloud-base height increased throughout the day, while the average cloud thickness decreased with time. In contrast to the other cloud properties, the average cloud-chord length remained nearly constant throughout the day. The sensitivity of the cloud properties to the year-to-year variability and to changes in low-level moisture were compared. The cloud-base height was found to be sensitive to both the year and the low-level moisture, the cloud thickness was much more sensitive to the year then to the low-level moisture, and the cloud fraction and cloud chord length were more sensitive to the low-level moisture than to the year. Distributions of the cloud-chord length over the ARCF SGP site were computed and were well fit by an exponential distribution. The contribution of clouds of each cloud-chord length to the total cloud fraction was computed, and it was found the clouds with a chord length of about 1 km contributed the most to the observed cloud fraction.

Berg, Larry K.; Kassianov, Evgueni I.

2008-07-01

114

Characterizing the Temporal Variability of Atmosphere Zenith Delay using a High Resolution Numerical Weather Model  

NASA Astrophysics Data System (ADS)

The temporal variations of the atmosphere delay affect the estimation of other parameters of interest from space geodetic observations in two ways: the estimated values depend on the characteristics of the variability, and the uncertainties of the estimated values also depend on those characteristics. An accurate assessment of the contribution of each source of error is important for evaluating which areas should be addressed to improve the measurements. A possible source of the statistical properties of the zenith atmosphere delay is a high horizontal resolution Numerical Weather Model (NWM). The actual zenith delays calculated from the NWM are not accurate enough to provide corrections to the space geodetic observations, but the statistics of the time variability may be useful as an external source of information on the temporal variations. This information may be in the form of a constraint on the change in zenith delay rate between segments of a piecewise linear model, or it may provide a daily value for the variance rate for a stochastic model as used in a Kalman filter estimation). To evaluate the accuracy of the NWM we will compare the statistical properties, such as the temporal structure function, of the zenith wet delays calculated from MM5 forecasts with three kilometer horizontal resolution with those from water vapor radiometer (WVR) measurements. The observation period is the CONT02 VLBI campaign in 2002 October. A WVR was operated at three of the eight participating VLBI sites. For geodetic VLBI data analysis the statistical properties of the atmosphere delay should cover time intervals as short as 30 seconds. For at least one WVR (Kokee, Hawaii) the sampling interval was sixteen seconds. For the MM5 forecasts the time step for the three kilometer resolution grid (the smallest of four nested grids) is only nine seconds. Comparison will also be made with the statistical model of Treuhaft and Lanyi (1987 Radio Science, V22, 251-265).

Niell, A. E.; Leidner, M.

2006-12-01

115

Earth Tides, Ocean Tides and Tidal Loading  

Microsoft Academic Search

The distortion of the Earth's gravitational potential field by the M2 ocean tide has been calculated, accounting for both the elastic deformation of the Earth and the self potential of the water. The potential field generated by the ocean tide is almost everywhere greater than a tenth, and over much of the ocean is half as large as the lunar

W. E. Farrell

1973-01-01

116

Introduction to Ocean Tides  

NSDL National Science Digital Library

Ocean tides profoundly impact coastal maritime operations. This module provides an introduction to the origin, characteristics, and prediction of tides. After introducing common terminology, the module examines the mechanisms that cause and modify tides, including both astronomical and meteorological effects. A discussion of tide prediction techniques and products concludes the module. This module includes rich graphics, audio narration, embedded interactions, and a companion print version.

Spangler, Tim

2006-09-22

117

HarborTides.com  

NSDL National Science Digital Library

HarborTides.com is a neat, user-friendly facility for tide information for over 2,500 harbors in the US (and Bermuda). Users may browse by state or search by zip code for information on high and low tides, sunrise and sunset, and longitude and latitude for every harbor. After filling out a form for free membership, users can also print out monthly tide tables.

118

Waves and Tides  

NSDL National Science Digital Library

In this 7-10 day investigation, learners develop an understanding of waves and tides and their motion through discussion, demonstration, and hands-on activities. Learners demonstrate wave motion in containers and create marigrams to show local tide data and to compare tide patterns from different parts of the world. Learners consider whether waves or tides account for the movement of bath toys to their final locations. This detailed lesson plan includes learner hand-outs, evaluation questions, and curricular connections.

Grant, Alaska S.

2011-01-01

119

What Causes Tides?  

ERIC Educational Resources Information Center

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…

Donovan, Deborah

2004-01-01

120

Moon and Tide Patterns  

NSDL National Science Digital Library

In this activity, students will use Moon and tide data from the internet to construct charts and answer questions about the patterns they see. They will be reminded that the Moon has something to do with ocean tides and will discover what the connections are. They will also discover when tides, moonrise and moonset, and phases of the Moon occur.

Passow, Michael

121

Variable spikes in tick-borne encephalitis incidence in 2006 independent of variable tick abundance but related to weather  

PubMed Central

Background The incidence of tick-borne encephalitis showed a dramatic spike in several countries in Europe in 2006, a year that was unusually cold in winter but unusually warm and dry in summer and autumn. In this study we examine the possible causes of the sudden increase in disease: more abundant infected ticks and/or increased exposure due to human behaviour, both in response to the weather. Methods For eight countries across Europe, field data on tick abundance for 2005–2007, collected monthly from a total of 41 sites, were analysed in relation to total annual and seasonal TBE incidence and temperature and rainfall conditions. Results The weather in 2006–2007 was exceptional compared with the previous two decades, but neither the very cold start to 2006, nor the very hot period from summer 2006 to late spring 2007 had any consistent impact on tick abundance. Nor was the TBE spike in 2006 related to changes in tick abundance. Countries varied in the degree of TBE spike despite similar weather patterns, and also in the degree to which seasonal variation in TBE incidence matched seasonal tick activity. Conclusion The data suggest that the TBE spike was not due to weather-induced variation in tick population dynamics. An alternative explanation, supported by qualitative reports and some data, involves human behavioural responses to weather favourable for outdoor recreational activities, including wild mushroom and berry harvest, differentially influenced by national cultural practices and economic constraints.

Randolph, Sarah E; Asokliene, Loreta; Avsic-Zupanc, Tatjana; Bormane, Antra; Burri, Caroline; Gern, Lise; Golovljova, Irina; Hubalek, Zdenek; Knap, Natasa; Kondrusik, Maceij; Kupca, Anne; Pejcoch, Milan; Vasilenko, Veera; Zygutiene, Milda

2008-01-01

122

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

PubMed

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

Gosztola, Beáta; Sárosi, Szilvia; Németh, Eva

2010-03-01

123

Spatial Variability of the Depth of Weathered and Engineering Bedrock using Multichannel Analysis of Surface Wave Method  

NASA Astrophysics Data System (ADS)

In this paper an attempt has been made to evaluate the spatial variability of the depth of weathered and engineering bedrock in Bangalore, south India using Multichannel Analysis of Surface Wave (MASW) survey. One-dimensional MASW survey has been carried out at 58 locations and shear-wave velocities are measured. Using velocity profiles, the depth of weathered rock and engineering rock surface levels has been determined. Based on the literature, shear-wave velocity of 330 ± 30 m/s for weathered rock or soft rock and 760 ± 60 m/s for engineering rock or hard rock has been considered. Depths corresponding to these velocity ranges are evaluated with respect to ground contour levels and top surface levels have been mapped with an interpolation technique using natural neighborhood. The depth of weathered rock varies from 1 m to about 21 m. In 58 testing locations, only 42 locations reached the depths which have a shear-wave velocity of more than 760 ± 60 m/s. The depth of engineering rock is evaluated from these data and it varies from 1 m to about 50 m. Further, these rock depths have been compared with a subsurface profile obtained from a two-dimensional (2-D) MASW survey at 20 locations and a few selected available bore logs from the deep geotechnical boreholes.

Anbazhagan, P.; Sitharam, T. G.

2009-03-01

124

Regional Differences in the Growing Incidence of Dengue Fever in Vietnam Explained by Weather Variability  

PubMed Central

Dengue fever is a major health problem in Vietnam, but its incidence differs from province to province. To understand this at the local level, we assessed the effect of four weather components (humidity, rainfall, temperature and sunshine) on the number of dengue cases in nine provinces of Vietnam. Monthly data from 1999 to 2009 were analysed by time-series regression using negative binomial models. A test for heterogeneity was applied to assess the weather-dengue association in the provinces. Those associations were significantly heterogeneous (for temperature, humidity, and sunshine: P < 0.001 heterogeneity test; for rainfall: P = 0.018 heterogeneity test). This confirms that weather components strongly affect dengue transmission at a lag time of 0 to 3 months, with considerable variation in their influence among different areas in Vietnam. This finding may promote the strategic prevention of dengue disease by suggesting specific plans at the local level, rather than a nationally unified approach.

Vu, Ha Hai; Okumura, Junko; Hashizume, Masahiro; Tran, Duong Nhu; Yamamoto, Taro

2014-01-01

125

Regional differences in the growing incidence of dengue Fever in Vietnam explained by weather variability.  

PubMed

Dengue fever is a major health problem in Vietnam, but its incidence differs from province to province. To understand this at the local level, we assessed the effect of four weather components (humidity, rainfall, temperature and sunshine) on the number of dengue cases in nine provinces of Vietnam. Monthly data from 1999 to 2009 were analysed by time-series regression using negative binomial models. A test for heterogeneity was applied to assess the weather-dengue association in the provinces. Those associations were significantly heterogeneous (for temperature, humidity, and sunshine: P < 0.001 heterogeneity test; for rainfall: P = 0.018 heterogeneity test). This confirms that weather components strongly affect dengue transmission at a lag time of 0 to 3 months, with considerable variation in their influence among different areas in Vietnam. This finding may promote the strategic prevention of dengue disease by suggesting specific plans at the local level, rather than a nationally unified approach. PMID:24808744

Vu, Ha Hai; Okumura, Junko; Hashizume, Masahiro; Tran, Duong Nhu; Yamamoto, Taro

2014-03-01

126

Star Gardens: Tides  

NSDL National Science Digital Library

In this activity students will learn that tides are caused by the gravitational pull of the moon and sun on the surface of the ocean. They will discover that tides are predictable changes in sea level that occur at regular intervals, and rise and fall roughly twice during each 24-hour period. Students will also find that tides follow the phases of the moon, with the highest and lowest tides occurring during the full and new moons. They will create a tide calendar by plotting a month-long tidal curve on an ordinary pictorial calendar. They will realize that because tides affect both the natural environment and human activities in many ways, it is important to know when they will occur.

127

Seasonal variation of the M 2 tide  

NASA Astrophysics Data System (ADS)

The seasonal cycle of the main lunar tidal constituent M 2 is studied globally by an analysis of a high-resolution ocean circulation and tide model (STORMTIDE) simulation, of 19 years of satellite altimeter data, and of multiyear tide-gauge records. The barotropic seasonal tidal variability is dominant in coastal and polar regions with relative changes of the tidal amplitude of 5-10 %. A comparison with the observations shows that the ocean circulation and tide model captures the seasonal pattern of the M 2 tide reasonably well. There are two main processes leading to the seasonal variability in the barotropic tide: First, seasonal changes in stratification on the continental shelf affect the vertical profile of eddy viscosity and, in turn, the vertical current profile. Second, the frictional effect between sea-ice and the surface ocean layer leads to seasonally varying tidal transport. We estimate from the model simulation that the M 2 tidal energy dissipation at the sea surface varies seasonally in the Arctic (ocean regions north of 60°N) between 2 and 34 GW, whereas in the Southern Ocean, it varies between 0.5 and 2 GW. The M 2 internal tide is mainly affected by stratification, and the induced modified phase speed of the internal waves leads to amplitude differences in the surface tide signal of 0.005-0.0150 m. The seasonal signals of the M 2 surface tide are large compared to the accuracy demands of satellite altimetry and gravity observations and emphasize the importance to consider seasonal tidal variability in the correction processes of satellite data.

Müller, Malte; Cherniawsky, Josef Y.; Foreman, Michael G. G.; von Storch, Jin-Song

2014-01-01

128

The Causes of Tides  

NSDL National Science Digital Library

This document explains the predictable and periodic movements of ocean waters that are known as tides and how they are produced by the gravitational forces of the moon and sun. It describes how gravitational attraction and centrifugal force create bulges on either side of the Earth (the high tides), and how two coinciding and simultaneous low tides occur at equal distances around the earth between them. It also explains tidal range and why it varies greatly with geographic location.

129

The Causes of Tides  

NSDL National Science Digital Library

This document explains the predictable and periodic movements of ocean waters that are known as tides and how they are produced by the gravitational forces of the moon and sun. It describes how gravitational attraction and centrifugal force create bulges on either side of the Earth (the high tides), and how two coinciding and simultaneous low tides occur at equal distances around the earth between them. It also explains tidal range and why it varies greatly with geographic location.

Oberrecht, Kenn

2007-01-30

130

Spatial variability of the characteristics of combined wet weather pollutant loads in Paris  

Microsoft Academic Search

An on-site observatory of urban pollutant loads in combined sewers has been created in Paris in order to investigate wet weather pollutant loads at different spatial scales. This observatory is composed of six urban catchments, covering areas from 41 to 2581ha. For a wide range of parameters including suspended solids (SS), volatile suspended solids (VSS), chemical oxygen demand (COD), biochemical

Mounira Kafi; J. Gasperi; R. Moilleron; M. C. Gromaire; G. Chebbo

2008-01-01

131

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

Microsoft Academic Search

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

Nephi A Walton; Mollie R Poynton; Per H Gesteland; Chris Maloney; Catherine Staes; Julio C Facelli

2010-01-01

132

Impact of Atmospheric Tides on Climate Models  

NASA Astrophysics Data System (ADS)

The main factor that determines the weather on the surface of the earth is the time variation of the position overhead sun. This single factor determines the time of the day or night, variation of the surface temperature, prevailing wind direction and therefore, precipitation, weather and climate at any location on the earth surface. The locus of this position can always be accurately determined astronomically and therefore it is possible to predict most weather parameters using weather models. Current climate models may be used to generate forecasts which have high degree of reliability. However, for prolonged periods, the reliability decreases significantly. Furthermore, most models may not be used to replicate past climates. While it is possible to explain the causes of some past weather anomalies it is not entirely possible to forecast future ones with considerable certainty. In this work, the effects of enhanced atmospheric tides resulting from unique solar-lunar geometries as well as those of known solar activities influencing the atmosphere will be investigated with a view to establishing their impact on forecast generated using climate models. The purpose is to increase the time-space reliability of the models. Enhanced atmospheric tides is seen to increase the height of the Hadley cell as well as decreasing the latitudinal base on which the cell is located. Because the spatial-temporal occurrence of an enhanced atmospheric is time-dependent, its effect on climate and weather parameters can accurately be predicted.

Gachari, Francis; Mulati, David M.; Mutuku, John N.

2010-05-01

133

Tide operated power generating apparatus  

SciTech Connect

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.

Kertzman, H. Z.

1981-02-03

134

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

SciTech Connect

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 conditions. In order to simulate substantial reaction progress over geologic time, one can benefit from the quasi-stationary state (QSS) approximation. A significant saving of computing time using QSS is demonstrated through the example. In addition, changes in porosity and permeability due to mineral dissolution and precipitation are also addressed in some degree. Even though oxidative weathering is sensitive to many factors, this work demonstrates that our model provides a comprehensive suite of process modeling capabilities, which could serve as a prototype for oxidative weathering processes with broad significance for geoscientific, engineering, and environmental applications.

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

1999-04-01

135

Tides and tidal energy  

Microsoft Academic Search

The present article reviews our understanding of the tides and of the flow of tidal energy through the oceans. The residence time for tidal energy in the oceans is short, and this results in relatively simple relationships between the observed pattern of tides at any port and the motions of the Moon and Sun about the Earth. The first part

D. J. Webb

1982-01-01

136

Contributions of weather variables for specific adaptation of rubber tree (Hevea brasiliensis Muell.- Arg) clones  

Microsoft Academic Search

The specific adaptation of 15 rubber tree (Hevea brasiliensis) clones was assessed by analyzing yield during a normal year (1997-98) and a year (1998-99) in which the yield was exceptional. Differences in yield in response to changes in weather conditions over the years were evident with clones RRII 203, RRIM 703, PB 5\\/51 and PB 235 which all exhibited a

P. M. Priyadarshan

2003-01-01

137

A variable vertical resolution weather model with an explicitly resolved planetary boundary layer  

NASA Technical Reports Server (NTRS)

A version of the fourth order weather model incorporating surface wind stress data from SEASAT A scatterometer observations is presented. The Monin-Obukhov similarity theory is used to relate winds at the top of the surface layer to surface wind stress. A reasonable approximation of surface fluxes of heat, moisture, and momentum are obtainable using this method. A Richardson number adjustment scheme based on the ideas of Chang is used to allow for turbulence effects.

Helfand, H. M.

1981-01-01

138

Studying the space weather variability of the high-latitude ionosphere by using a physics-based data assimilation model  

NASA Astrophysics Data System (ADS)

The high-latitude ionosphere is a very dynamic region in the solar-terrestrial environment. Frequent disturbances in the region can adversely affect numerous military and civilian technologies. Accurate specifications and forecasts of the high-latitude electrodynamic and plasma structures have fundamental space weather importance for enabling mitigation of adverse effects. We developed a data assimilation model for the high-latitude ionosphere. The model consists of a set of first-principle physical models and an ensemble Kalman filter and assimilates the real-time (or rear real-time) observational measurements. Presently, the model can ingest the magnetic perturbation from the ground-based magnetometers in the high-latitude regions, magnetic measurements of IRIDIUM satellites, SuperDARN line-of-sight velocity, and in-situ drift velocity measured by DMSP satellites. In this presentation, we will show the preliminary results of a systematic study of the space weather variability of the electrodynamic and plasma structures in the high-latitude ionosphere by using our data assimilation model. The study covers the periods of various seasons and geomagnetic conditions. With these results, we would demonstrate the dynamic nature of the high-latitude ionosphere and elucidate the importance of the data assimilation technique for accurate specification and forecasting of space weather.

Zhu, L.; Schunk, R. W.; Scherliess, L.; Eccles, J. V.; Sojka, J. J.

2012-12-01

139

Resonant dynamic tides and apsidal motion in close binaries  

Microsoft Academic Search

The resonance of a dynamic tide with a free oscillation mode in a component of a close binary system of stars is treated by means of a two-time variable expansion procedure. The treatment is developed with respect to a frame of reference corotating with the star. Both the free oscillation mode and the dynamic tide are considered as linear, isentropic

P. Smeyers; B. Willems; T. Van Hoolst

1998-01-01

140

Internal-tide generation and destruction by shoaling internal tides  

Microsoft Academic Search

Internal-tide generation is usually predicted from local topography, surface tides, and stratification. However, internal tides are often observed to be unrelated to local spring-neap forcing, appearing intermittently in 3–5 day bursts. Here we suggest a source of this intermittency by illustrating how remotely-generated shoaling internal tides induce first-order changes in local internal-tide generation. Theory, numerical simulations, and observations show that

S. M. Kelly; J. D. Nash

2010-01-01

141

Dynamics of ocean tides  

SciTech Connect

Ocean tide information can solve vital problems in oceanology and geophysics. Elastic properties of the Earth's crust, tidal gravity variations and deviations in trajectories of artificial satellites can be studied from the dynamics of ocean tides. This book contains mathematical models and applications on several problems related to ocean tide dynamics. The first part serves as an introduction to studies of tidal dynamics equations and the application in experimental studies. Specific problems like free oscillations and forced tidal oscillations in the oceans and the ocean-shelf system are discussed. The book deals with tidal flow in the bottom boundary layer. Data and models are presented and experimental and theoretical results are compared.

Maarchuk, G.I.; Kagan, B.A. (P.P. Shirshov Inst. of Oceanology, Moscow (SU))

1989-01-01

142

Tides and tsunamis  

NASA Technical Reports Server (NTRS)

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.

Zetler, B. D.

1972-01-01

143

A semiparametric multivariate and multi-site weather generator with a low-frequency variability component for use in bottom-up, risk-based climate change assessments  

NASA Astrophysics Data System (ADS)

A daily weather generator is presented with greater ability to support bottom-up vulnerability assessments under climate change for a wide range of socio-economic systems sensitive to different aspects of climate variability and change. The proposed stochastic model has several components, including 1) a Markov Chain and k-nearest-neighbor (KNN) resampling scheme to simulate spatially-distributed, multivariate weather variables over a region, 2) a wavelet decomposition coupled to an autoregressive model to account for structured, low-frequency climate oscillations, and 3) a quantile mapping procedure to enforce long-term distributional shifts in weather variables under climate change. The Markov Chain is used to better represent wet and dry spell statistics while the KNN bootstrap resampler preserves the spatial covariance structure of the weather variables. A wavelet-based autoregressive model is applied to annual climate over the region and used to modulate the transition probabilities of the Markov Chain, embedding appropriate low-frequency structure within the daily weather generation process. The time series of simulated weather variables are then adjusted using a quantile mapping procedure to enforce distributional shifts hypothesized under climate change. The proposed model enables the generation of realistic time series of climate variables that exhibit changes to both lower-order and higher-order statistics at long-term (inter-annual), mid-term (seasonal), and short-term (daily) timescales. The tool can be coupled with impact models of socio-economic systems in a bottom-up risk assessment to determine the potential climate changes under which the system is most vulnerable. An application of the proposed weather generator and its use in a bottom-up risk assessment under climate change is presented for a flood control reservoir in Iowa.

Steinschneider, S.; Brown, C. M.

2012-12-01

144

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

NASA Astrophysics Data System (ADS)

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

Devasthale, A.; Norin, L.

2014-06-01

145

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

NASA Astrophysics Data System (ADS)

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

Devasthale, A.; Norin, L.

2013-12-01

146

Carbon dioxide variability during cold front passages and fair weather days at a forested mountaintop site  

NASA Astrophysics Data System (ADS)

This study describes temporal carbon dioxide (CO 2) changes at a new meteorological site on a mountaintop in the Virginia Blue Ridge Mountains during the first year of measurements. Continental mountaintop locations are increasingly being used for CO 2 monitoring, and investigations are needed to better understand measurements made at these locations. We focus on CO 2 mixing ratio changes on days with cold front passages and on fair weather days. Changes in CO 2 mixing ratios are largest during cold front passages outside the growing season and on clear, fair weather days in the growing season. 67% (60%) of the frontal passages during the non-growing (growing) season have larger postfrontal than prefrontal CO 2 mixing ratios. The increase in CO 2 mixing ratio around the frontal passage is short-lived and coincides with changes in CO and O 3. The CO 2 increase can therefore be used as an additional criterion to determine the timing of frontal passages at the mountaintop station. The CO 2 increase can be explained by an accumulation of trace gases along frontal boundaries. The magnitude and duration of the CO 2 increase is affected by the wind speed and direction that determine the source region of the postfrontal air. Southward-moving fronts result in the largest prolonged period of elevated CO 2, consistent with the postfrontal advection of air from the Northeastern United States where anthropogenic contributions are relatively large compared to other areas in the footprint of the mountaintop station. These anthropogenic contributions to the CO 2 changes are confirmed through concurrent CO measurements and output from NOAA's CarbonTracker model.

Lee, Temple R.; De Wekker, Stephan F. J.; Andrews, Arlyn E.; Kofler, Jonathan; Williams, Jonathan

2012-01-01

147

Students' Understanding of Tides.  

ERIC Educational Resources Information Center

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)

Viiri, Jouni

2000-01-01

148

The Earth Tides.  

ERIC Educational Resources Information Center

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)

Levine, Judah

1982-01-01

149

The Role of Gravity Waves in Modulating Atmospheric Tides  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

150

Weather variability and interannual responses of the vegetation and crops in Cordoba-Argentina assessed by AVHRR derived vegetation indices  

NASA Astrophysics Data System (ADS)

Advanced Very High Resolution Radiometer (AVHRR) based vegetation indices are widely accepted as good indicators for providing vegetation properties and associated changes for large scale geographic regions. Also, their capability to indicate moisture conditions makes them an important data source for monitoring climate variations and droughts. The objective of this study was to assess the seasonal interannual responses of vegetation and crops to the weather variability. Time-series analysis of AVHRR Normalized Difference Vegetation Index (NDVI) and vegetation health indices weekly composite data collected during 1981-2003 were used to generate the seasonal vegetation curves for each of the departments (administrative unite) of the Cordoba province in Argentina, and to calculate the onset of the growing seasons. Yield series of corn and soybean for each of the departments were analyzed against AVHRR derived indices and seasonal precipitation data from the meteorological stations in the province. Results from the analysis showed that the variability of the indices serves as good proxy for identifying climate variations and thus provide insights into understanding the regional climate carrying capacity, the climate anomalies and the effects of the climate variability on vegetation, on the onset and length of the growing season and on the yields of agricultural crops.

Seiler, R.; Kogan, F.; Vinocur, M.

151

Modeling the variability of solar radiation data among weather stations by means of principal components analysis  

Microsoft Academic Search

Measurements of global terrestrial solar radiation (Rs) are commonly recorded in meteorological stations. Daily variability of Rs has to be taken into account for the design of photovoltaic systems and energy efficient buildings. Principal components analysis (PCA) was applied to Rs data recorded at 30 stations in the Mediterranean coast of Spain. Due to equipment failures and site operation problems,

Manuel Zarzo; Pau Martí

2011-01-01

152

Synoptic Scale Weather Patterns Associated with Annual Snow Accumulation Variability in North-Central Greenland  

NASA Astrophysics Data System (ADS)

Previous studies on the synoptic forcing of high elevation areas of central Greenland have mostly relied on ice cores, snow pits, mesoscale models, and climate models. In this study, a radar-measured 118-year annual snow accumulation record (1889-2006) along a 375 km traverse between NGRIP and NEEM ice camps in Greenland is used. A Self-Organizing Maps (SOM) algorithm is applied to a reanalysis forecast model (20th Century Reanalysis Data Version 2 (1870 to 2008)) to identify recurring patterns in the sea level pressure (SLP) field that impact meteorological processes and explain annual variations of accumulation over North-Central Greenland for the 118 year period. The SOM algorithm identified 36 representative daily SLP patterns over the North Atlantic region. Synoptic weather patterns shown in these SLP patterns include cyclone splitting, cyclone-blocking, and cyclone tracks indicating changes in cyclone position and cyclone intensity. Based on radar-measured annual snow accumulation, common SLP patterns for wet years (more accumulation) over North-Central Greenland are characterized by low pressure systems surrounding Greenland or cyclones approaching the west coast of Greenland, conveying moisture through a topographically lifted onshore flow; these patterns are mostly associated with negative/neutral NAO index. In dry years (less accumulation), prevailing patterns are characterized by cyclones positioned a long distance away in the Atlantic Ocean south of Greenland, which are mainly associated with a positive NAO index. Extreme wet year prevailing patterns of NGRIP-NEEM traverse southern portion show a distinct departure from the above described North-Central Greenland general patterns by having more frequent positive-NAO days, which is similar to dry and extreme dry years. Model precipitation amounts over North-Central Greenland from the 20th Century Reanalysis Data are found to be overestimated by up to 10 cm/year.

Shu, Chen

153

Climate Variability, Weather and Enteric Disease Incidence in New Zealand: Time Series Analysis  

PubMed Central

Background Evaluating the influence of climate variability on enteric disease incidence may improve our ability to predict how climate change may affect these diseases. Objectives To examine the associations between regional climate variability and enteric disease incidence in New Zealand. Methods Associations between monthly climate and enteric diseases (campylobacteriosis, salmonellosis, cryptosporidiosis, giardiasis) were investigated using Seasonal Auto Regressive Integrated Moving Average (SARIMA) models. Results No climatic factors were significantly associated with campylobacteriosis and giardiasis, with similar predictive power for univariate and multivariate models. Cryptosporidiosis was positively associated with average temperature of the previous month (??=? 0.130, SE?=? 0.060, p <0.01) and inversely related to the Southern Oscillation Index (SOI) two months previously (??=? ?0.008, SE?=? 0.004, p <0.05). By contrast, salmonellosis was positively associated with temperature (? ?=?0.110, SE?=?0.020, p<0.001) of the current month and SOI of the current (? ?=?0.005, SE?=?0.002, p<0.050) and previous month (? ?=?0.005, SE?=?0.002, p<0.05). Forecasting accuracy of the multivariate models for cryptosporidiosis and salmonellosis were significantly higher. Conclusions Although spatial heterogeneity in the observed patterns could not be assessed, these results suggest that temporally lagged relationships between climate variables and national communicable disease incidence data can contribute to disease prediction models and early warning systems.

Lal, Aparna; Ikeda, Takayoshi; French, Nigel; Baker, Michael G.; Hales, Simon

2013-01-01

154

Spatial variability of trace metals and inorganic nutrients in surface waters of Todos Santos Bay, México in the summer of 2005 during a red tide algal bloom.  

PubMed

Dissolved and particulate metals (Ag, Cd, Co, Cu, Ni, and Zn) and nutrients (PO(4), NO(3), and H(4)SiO(4)) were measured in Todos Santos Bay (TSB) in August 2005. Two sources producing local gradients were identified: one from a dredge discharge area (DDA) and another south of the port and a creek. The average concentrations of dissolved Cd and Zn (1.3 and 15.6 nM, respectively) were higher by one order of magnitude than the surrounding Pacific waters, even during upwelling, and it is attributed to the presence of a widespread and long-lasting red tide coupled with some degree of local pollution. A clear spatial gradient (10 to 6 pM), from coast to offshore, of dissolved Ag was evident, indicating the influence of anthropogenic inputs. The particulate fraction of all metals, except Cu, showed a factor of ~3 decrease in concentrations from the DDA to the interior of the bay. The metal distributions were related to the bay's circulation by means of a numerical model that shows a basically surface-wind-driven offshore current with subsurface compensation currents toward the coast. Additionally, the model shows strong vertical currents over the DDA. Principal component analysis revealed three possible processes that could be influencing the metal concentrations within TSB: anthropogenic inputs (Cd, Ag, and Co), biological proceses (NO(3), Zn, and Cu), and upwelling and mixing (PO(4), H(4)SiO(4), Cd, and Ni). The most striking finding of this study was the extremely high Cd concentrations, which have been only reported in highly contaminated areas. As there was a strong red tide, it is hypothesized that the dinoflagellates are assimilating the Cd, which is rapidly remineralized and being concentrated on the stratified surface layers. PMID:18726538

Lares, M L; Marinone, S G; Rivera-Duarte, I; Beck, A; Sañudo-Wilhelmy, S

2009-05-01

155

Waves: Internal Tides  

NASA Technical Reports Server (NTRS)

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.

Ray, Richard D.

1999-01-01

156

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

PubMed Central

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.

Hernandez, Luis; Baladron, Carlos; Aguiar, Javier M.; Calavia, Lorena; Carro, Belen; Sanchez-Esguevillas, Antonio; Cook, Diane J.; Chinarro, David; Gomez, Jorge

2012-01-01

157

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

NASA Astrophysics Data System (ADS)

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 model was run by using observed meteorological data and calibrated in the Upper Mississippi River Basin (UMRB) from 1980 to 2010. Subsequently, a simulation based on an offline linkage of WRF and VIC was performed in the UMRB with the calibrated parameters established above from 2006 to 2009. Standard measured meteorological inputs to VIC were replaced by WRF meteorological variables. A spatiotemporal comparison of offline simulated ET, SM, runoff, and baseflow produced by the VIC calibrated run (base data) and by the offline linkage run was conducted. The results showed that the offline linkage of VIC with WRF was able to achieve good agreement in the simulation of monthly and daily soil moisture, and monthly evaporation. This suggests the VIC linkage should function without causing a large change in the moisture budget. However, the offline linkage showed most disagreement in daily and monthly runoff, and baseflow which is related to errors in WRF precipitation.

Tang, Chunling; Dennis, Robin L.

2014-05-01

158

Types of Tides and Tidal Currents  

NSDL National Science Digital Library

This text discusses differences in ocean tides. Along America's Atlantic Coast, two high and low tides occur daily. Such tides are called semidiurnal. On the north shore of the Gulf of Mexico, the tide is diurnal, meaning that it moves in and out again once a day while in the Pacific Northwest, there are mixed tides, two highs and two lows a day, characterized by significant disparity between successive tides. The site also explains flood current or flood tide, ebb current or ebb tide, and slack water or slack tide. There is a detailed discussion of spring tide and neap tide and also an explanation of the difference between riptide and tiderip.

159

Tides and Water Levels  

NSDL National Science Digital Library

This site serves as a gateway to three sections devoted to learning about tides and water levels: an online tutorial, an list of links to tidal resources, and formal lesson plans. The tutorial is an overview of the complex systems that govern the movement of tides and water levels. It is content rich, is presented in easy-to-understand language, and includes many illustrative and interactive graphics to visually enhance the text. The links direct users to specific tidal and current data offered within the National Ocean Service and National Oceanic and Atmospheric Administration's family of products. Lesson plans integrate information presented in the tutorial with online data. These lesson plans have been developed for students in grades 9-12 and focus on the forces that cause and effect tides, analysis of the variations in tidal patterns and what conditions may cause them, and the effect of lunar cycles on living organisms.

160

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

161

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

PubMed

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. PMID:22855350

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

2013-07-01

162

Ocean Tide Loading Computation  

NASA Technical Reports Server (NTRS)

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.

Agnew, Duncan Carr

2005-01-01

163

Florida Red Tide Current Status  

NSDL National Science Digital Library

This Fish and Wildlife Research Institute website provides links to several Florida-based red tide sites. These sites include the current status of Florida's red tide, a photo gallery of red tide distribution maps, and regional Florida red tide statuses. The site expands further on its research and contains information on the Florida manatee, Florida panther, freshwater, geographic information systems/mapping, habitat, saltwater and wildlife. This is a nice resource for a broad overview of Florida ecosystems and natural resources.

2009-09-18

164

Science 101: What causes tides?  

NSDL National Science Digital Library

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 relation to the Sun, but is also influenced by other factors. This is a brief introduction to what causes tides.

Donovan, Deborah

2004-07-01

165

Tides in Titan  

NASA Technical Reports Server (NTRS)

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.

Rappaport, Nicole J.

1997-01-01

166

Ocean tide energy converter  

SciTech Connect

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.

Rainey, D.E.

1980-06-24

167

Florida's Red Tide Infestation  

NSDL National Science Digital Library

This CBS news article reports a toxic algae bloom that spread along the Florida's west coast in 2001, threatening the wildlife of Tampa Bay's estuary. The article briefly discusses the cause of the red tide and its affect on the shellfish industry.

News, Cbs

168

Theory of Bodily Tides.  

National Technical Information Service (NTIS)

Different theories of bodily tides assume different forms of dependence of the angular lag (delta) upon the tidal frequency X (chi). In the old theory (Gerstenkorn 1955, MacDonald 1964, Kaula 1964) the geometric lag angle is assumed constant, while the ne...

M. Efroimsky V. Lainey

2007-01-01

169

Dynamic Elastic Tides  

NASA Astrophysics Data System (ADS)

We present a new formulation of solid body tides where tidal displacements are modeled by a sum of excited elastic modes. We reproduce the classic expressions for tidal dissipation, despinning rate, and evolution of semimajor axis and eccentricity in the constant time lag tidal model. Our formulation is extendable to other rheologies and applicable to solar system bodies and super-Earths.

Meyer, Jennifer; Wisdom, J.

2011-04-01

170

Hurricane Sandy Storm Tide Mapper  

NSDL National Science Digital Library

United States Geological Survey (USGS) provides real-time map-based information from USGS storm tide sensors. The data is reflected on the Hurricane Sandy Tide Mapper. The mapper provides location information, site photos and data for storm tide and inland flooding. In addition, the data from these sensors is used to create models of the precise time the storm-tide arrived, how ocean and inland water levels changed during the storm, the depth of the storm-tide throughout the event, and how long it took for the water to recede.

171

Red Tide in the Northeast  

NSDL National Science Digital Library

This Rhode Island Sea Grant fact sheet provides information about red tide algal blooms in New England. It addresses where and when red tides occur, how to know if shellfish are safe to consume, and other important facts about red tide. The site features a black and white picture of the dinoflagellate responsible for red tide in New England and a regional map of where infected shell fish have been found. It also features links to other red tide related sites and a list of pertinent reading material.

Ely, Elenor; Ross, Neil W.; Island, Sea G.

172

South China Sea internal tide\\/internal waves-impact on the temporal variability of horizontal array gain at 276 Hz  

Microsoft Academic Search

The temporal variability of the spatial coherence of an acoustic signal received on a bottomed horizontal array has been calculated for 276-Hz narrow-band signals. A conventional plane wave beamformer was applied to the received signals. The temporal variability of the array's omnipower, beam power, and array gain are related to variability in the sound-speed field. The spectral characteristics of array

Marshall H. Orr; Bruce H. Pasewark; Stephen N. Wolf; James F. Lynch; Theodore Schroeder; Ching-Sang Chiu

2004-01-01

173

Energy Delivery to Cliffs from Waves, Tides and Storms  

NASA Astrophysics Data System (ADS)

The energy delivered to hard rock cliffs from waves, tides and storms is acknowledged as a key control of cliff erosion, due to the influence on the effectiveness of mechanical and hydraulic processes. The direct impact and variability of wave energy and its influence on rock cliffs remains poorly constrained. Questions remain around the relative impact that waves, tides and storms have on energy delivery to the coast and therefore on cliff evolution. The results of this paper begin to unpick these three influences. These results are made more significant in terms of understanding the future likely impact of sea-level change, but more widely in clarifying the relative significance of marine to sub-aerial weathering processes in controlling cliff failure and rocky coast evolution. It has been demonstrated that wave impact against cliffs results in microseismic ground motions, which can be used as a proxy for energy delivery to the cliff mass. This paper presents the findings of a study that exploits data from a 10 instrument 3D seismometer array, combined with an intensive program of monitoring of marine and aerial conditions on and near the cliff section. The study site on the coast of northeast England, consists of numerous strata of Jurassic mudstones, sandstones and shales. The high tidal range and exposure to frequent stormy conditions results in wide day-to-day variations in environmental conditions. The results enable assessment of the sensitivity of rocky cliff ground motion to wave characteristics such as height and period, tidal characteristics including levels and durations of inundation, and wind and rainfall events, explored using spectral and wavelet analysis. The results provide a quantification of the relative energy delivery of these different forcing mechanisms, and hence provide insight of likely cliff responses to future climate change scenarios related to combined changes in storm severity and sea-level.

Norman, E. C.; Rosser, N. J.; Lim, M.; Petley, D. N.

2009-12-01

174

Altimetry, Orbits and Tides  

NASA Technical Reports Server (NTRS)

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.

Colombo, O. L.

1984-01-01

175

Tides of io  

Microsoft Academic Search

Jupiter's satellite Io is the most active earth-like planetary body in the solar system with a surface heat flow of, at least, 2.5 W m–2, a resurfacing rate of 1.3 cm a–1, and, possibly, a self-sustained magnetic field. It is universally accepted that the activity is driven by tidal energy dissipated in Io's mantle. Tides with amplitudes two orders of

Tilman Spohn

1997-01-01

176

High Tide on Io!  

NSDL National Science Digital Library

This site provides a discussion of movement on the surface of Io, a satellite of Jupiter. It makes comparisons between ground movement on Io, where the ground itself moves up and down like an elevator taking people to the top and bottom of a 30-story building, and the earth, where similar ground tides cause total movements of only 8 inches. Galileo spacecraft and its visit to Io are briefly described.

177

Dynamic Elastic Tides  

NASA Astrophysics Data System (ADS)

We present a formulation for solid body tides that includes the frequency dependence of the tidal dissipation in a self-consistent, modular way. We derive general expressions for tidal heating and rate of change of semimajor axis and eccentricity. We then specify a Kelvin-Voigt rheology, which corresponds to a constant time lag tidal model commonly used in the literature. We verify that our model produces the classical expressions and present several new expansions to high eccentricity.

Meyer, J.; Wisdom, J.

2011-10-01

178

Climate-dependent sediment production: numerical modeling and field observations of variable grain size distributions from heterogeneous hillslope weathering of fractured basalt flows, Kohala Peninsula, Hawaii  

NASA Astrophysics Data System (ADS)

We present a numerical model for hillslope sediment production that includes climate-dependent chemical weathering rates and bedrock fracture spacings, and predicts how grain size distributions vary with climate and hillslope erosion rate. Understanding sediment preparation, or the in situ reduction of fractured bedrock to coarse sediment by heterogeneous weathering on hillslopes, is critical to understanding the evolution of mountainous landscapes, as sediment supply rates and size distributions can strongly influence river incision rates. The majority of soil production models assume a homogenous substrate and uniform weathering front, and therefore do not track the size of rock fragments and corestones, which become the sediment supplied to channels by hillslope erosion. Our model is inspired by the Kohala Peninsula on the big island of Hawaii, which has a gradient of mean annual precipitation (MAP) spanning over an order of magnitude that has been shown to influence the weathering rates of the basalt. Previous geochemical studies have constrained climate-dependent weathering rates for local soil production. Using these inputs, we developed a kinetics-based numerical model for the chemical weathering of initially fractured basalt into soil and coarse sediment over 150ky. Following first-order reaction kinetics, chemical weathering in the model decreases exponentially with both depth below the surface and time. The model starts with a column of repeating basalt flows (typically 1 m thick), each with fracture spacing distributions consistent with thermal-mechanical cooling characteristics. Each individual fracture-bound block is assumed to weather from the surface inwards, similar in form to a weathering rind. Since the model is constructed of discrete blocks, larger blocks remain as unweathered corestones (the "sediment"), surrounded by weathered material. In addition to a MAP-dependent initial surface weathering rate and rate constant, climate is also reflected in the length scale for the reduction in chemical weathering below the surface, or the flushing depth. The flushing depth is assumed to scale linearly with MAP, but decreases exponentially with increasing soil depth, as soil capillarity will imbibe infiltration. Modeling six MAP regimes between 500 and 3000 mm produces a non-linear increase in soil depths from 0.59 m soil to 5.15 m, which is broadly consistent with field observations from Kohala Peninsula. The median corestone grain size (D50) was calculated at model completion for the 20 blocks below the soil-rock interface. In the driest regime the D50 was 98% of that for the initial column, while the D50 for the wettest regime was 56% of the initial. This sediment preparation model predicts soil depths and tracks particle size reduction with variable climate-dependent weathering rates. Incorporating this type of model into sediment-transport dependent landscape evolution models may be the key to understanding the systematic differences in topography across spatially variable climate gradients, such as Kohala Peninsula.

Murphy, B. P.; Johnson, J. P.

2012-12-01

179

Deep sea tides determination from GEOS-3  

NASA Technical Reports Server (NTRS)

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.

Maul, G. A.; Yanaway, A.

1978-01-01

180

On charting global ocean tides  

NASA Astrophysics Data System (ADS)

This review article highlights the three-century development of our scientific understanding of ocean tides, culminating through myths, paradoxes, and controversies in a global tide model that now permits the prediction of the instantaneous total tide anywhere in the open oceans with an accuracy of better than 10 cm. All major aspects of tidal research, including empirical, mathematical, and empirical-mathematical methods, are considered. Particular attention is drawn to the most recently developed computerized techniques comprehending hydrodynamical dissipation and secondary tide-generating forces, finite-differencing schemes, geometric boundary and bathymetry modeling, and hydrodynamical interpolation of properly selected empirical tide data. Numerous computer experiments are mentioned that were carried out by various researchers in order to evaluate the magnitudes of the featured effects. Further possible improvements are mentioned, especially in nearshore areas, in the Arctic Sea, and near Antarctica, where empirical tide and bathymetry data are either rough or marginal.

Schwiderski, Ernst W.

1980-02-01

181

Tides of the Caribbean Sea  

SciTech Connect

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.

Kjerfve, B.

1981-05-20

182

Seasonal and interannual variability of phytoplankton, nutrients, TCO 2 , p CO 2 , and O 2 in the eastern subarctic Pacific (ocean weather station Papa)  

Microsoft Academic Search

A coupled, one-dimensional ecosystem\\/carbon flux model is used to simulate the seasonal and interannual variability of phytoplankton, nutrients, TCO2 ,O 2, and pCO2 at ocean weather station Papa (OWS P at 50N, 145W). The 23-year interannual simulation (1958 -1980) is validated with available data and analyzed to extend seasonal and interannual variations beyond the limited observational records. The seasonal cycles

Sergio R. Signorini; Charles R. McClain; James R. Christian; C. S. Wong

2001-01-01

183

Seasonal and interannual variability of phytoplankton, nutrients, TCO2, pCO2, and O2 in the eastern subarctic Pacific (ocean weather station Papa)  

Microsoft Academic Search

A coupled, one-dimensional ecosystem\\/carbon flux model is used to simulate the seasonal and interannual variability of phytoplankton, nutrients, TCO2, O2, and pCO2 at ocean weather station Papa (OWS P at 50°N, 145°W). The 23-year interannual simulation (1958-1980) is validated with available data and analyzed to extend seasonal and interannual variations beyond the limited observational records. The seasonal cycles of pCO2

Sergio R. Signorini; Charles R. McClain; James R. Christian; C. S. Wong

2001-01-01

184

Thermal Tide Observations with the Mars Climate Sounder  

NASA Astrophysics Data System (ADS)

We present the results of an analysis of thermal tides using data from the Mars Climate Sounder (MCS). These data include both depth-weighted atmospheric temperatures (15?m brightness temperatures) and temperature profiles retrieved from limb radiance measurements. The depth-weighted temperatures (~30 Pa) are particularly useful for assessing seasonal variations and interannual variability as, unlike the profile retrievals, they are not compromised by dust storm events or thick layers of water ice clouds. The relatively recent addition of cross-track limb viewing provides broader local time coverage (at roughly 6 unequally spaced local times) that results in improved characterization of the thermal tides over the nominal twice daily observations provided by the along-track viewing. The additional local time coverage enables the identification of the amplitude and phase structure of the migrating diurnal and semi-diurnal tides. Tides are the atmospheric response to diurnally varying forcing and the migrating semi-diurnal tide is particularly sensitive to radiative heating by dust and water ice clouds. The additional local time coverage enables us to better constrain these tide modes and evaluate their response to seasonally evolving aerosol loading. We compare the MCS observations with results from the GFDL Mars global circulation model and discuss the relationship between aerosol forcing and temperature response. We find further evidence that water ice clouds make a significant contribution to tide forcing, as initially described in Kleinboehl et al. (GRL, 2013). The increased number of local time observations also allows the distinction between stationary planetary waves and non-migrating semi-diurnal tides, and the unambiguous differentiation of eastward- and westward-propagating non-migrating tides. Eastward propagating, diurnal period Kelvin waves are found to be particularly prominent in the upper atmosphere and these appear to have a well-defined seasonal cycle.

Wilson, R.; Guzewich, S.; Banfield, D. J.; Kleinboehl, A.

2013-12-01

185

NOAA: About Water Levels, Tides and Currents  

NSDL National Science Digital Library

A comprehensive lesson on what causes tides, current and past techniques for predicting tides, how and why water level is measured, and the challenges of measuring water currents. Site provides additional links to other NOAA tide resources.

186

The ultimate high tide  

SciTech Connect

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.

Dean, R.G. (Florida Dept. of Natural Resources, Tallahassee (USA))

1990-01-01

187

Tide gate valve  

SciTech Connect

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.

Raftis, S. G.

1985-01-08

188

The King of Tides  

NSDL National Science Digital Library

This well-constructed WebQuest begins with the announcement: âThe moon has been accused of causing the tides! Using real data collected from the Internet, your teamâs job is to bring proof one way or another!â The group task, the process for finding data and establishing proof, and the evaluation are outlined and explained clearly. However, as on all WebQuests, you will have to check the site addresses given, since Web addresses change or disappear over time. The two-week project, which depends on analysis of real data, culminates in a final report to the court.

Byles, Bill

2003-11-21

189

Population dynamics of red tide dinoflagellates  

NASA Astrophysics Data System (ADS)

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 (?) of the vegetative phase. It is argued that r is strategically adapted to seasonal cycles and long term environmental variability, while ? reflects tactical needs (timing) and constraints (grazers, parasites) on vegetative growth.

Wyatt, Timothy; Zingone, Adriana

2014-03-01

190

International Symposium on Earth Tides.  

National Technical Information Service (NTIS)

The Sixth International Symposium on Earth Tides was held in France at the University of Strasbourg, Sept. 15-20, 1969. It was organized by the Permanent Commission on Earth Tides, International Association of Geodesy, IUGG. The highlights of the symposiu...

B. D. Zetler

1970-01-01

191

Tides in water saturated rock  

Microsoft Academic Search

Analysis of water table records from wells or boreholes often reveals the presence of tidal fluctuations. Amplitudes of well tides can attain several centimeters when the well or borehole is open to a confined aquifer. The phenomenon reflects extension and compression cycles of the aquifer rock, i.e. volume strain tides of a water saturated formation. Besides tidal fluctuations, barometric pressure

Hans-Joachim Kctmpel

192

Tide pushing shellfishers into red  

NSDL National Science Digital Library

This USA Today article provides very general information about the 2005 red tide outbreak off the Gulf of Maine. It offers possible explanations for the outbreak, what is being done to protect people from hazards related to red tide, and how the outbreak has devastated local shellfishers.

Hampson, Rick; Today, Usa

193

Tides of the British Seas  

ERIC Educational Resources Information Center

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)

Sandon, Frank

1975-01-01

194

Europa Tide Movie  

NASA Technical Reports Server (NTRS)

[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.

2007-01-01

195

The Potential Impacts of Climate Variability and Change on Health Impacts of Extreme Weather Events in the United States  

Microsoft Academic Search

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

Gregg Greenough; Michael McGeehin; Susan M. Bernard; Juli Trtanj; Jasmin Riad; David Engelberg

2001-01-01

196

Types of Tides and Tidal Currents  

NSDL National Science Digital Library

This text discusses differences in ocean tides. Along America\\'s Atlantic Coast, two high and low tides occur daily. Such tides are called semidiurnal. On the north shore of the Gulf of Mexico, the tide is diurnal, meaning that it moves in and out again once a day while in the Pacific Northwest, there are mixed tides, two highs and two lows a day, characterized by significant disparity between successive tides. The site also explains flood current or flood tide, ebb current or ebb tide, and slack water or slack tide. There is a detailed discussion of spring tide and neap tide and also an explanation of the difference between riptide and tiderip.

Oberrecht, Kenn

2007-01-29

197

Weather Forecasting  

NSDL National Science Digital Library

This activity is designed to give students an understanding of how to forecast weather and how to use weather reports for their personal benefit. They will be able to tell what weather is, read weather instruments, understand basic cloud formations in relation to the weather, and make forecasts for two days in advance.

198

Lunar Core and Tides  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

199

Weather Watch  

ERIC Educational Resources Information Center

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

Bratt, Herschell Marvin

1973-01-01

200

Spatial variability in mycorrhizal hyphae and nutrient and water availability in a soil-weathered bedrock profile  

Microsoft Academic Search

We documented the spatial distribution, abundance and molecular diversity of mycorrhizal hyphae and physical and chemical properties of soil-weathered bedrock in a chaparral community that experiences seasonal drought. Because plants in this community were known to rely on bedrock-stored water during the summer, the data were used to evaluate the potential role of mycorrhizal hyphae in accessing bedrock-stored water during

L. M. Egerton-Warburton; R. C. Graham; K. R. Hubbert

2003-01-01

201

The Effect of Ocean and Earth Tides on the SemiDiurnal Lunar Air Tide  

Microsoft Academic Search

The effects of the earth and ocean tides on the semi-diurnal lunar tide in the atmosphere have been ignored in nearly all studies of this air tide. Elementary arguments show that these boundary effects are not trivial. Using linear theory we calculated the combined effect of the lunar potential, the earth tide, and the ocean tide on a realistic model

Anthony Hollingsworth

1971-01-01

202

M2 world ocean tide from tide gauge measurements  

SciTech Connect

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.

Francis, O.; Mazzega, P. (CNES/CNRS, Toulouse (France))

1991-06-01

203

Hydrochemical and Isotopic Constraints on the Temporal and Spatial Variability of Chemical Weathering and CO2 Fluxes: An Example From the Australian Victorian Alps  

NASA Astrophysics Data System (ADS)

Water from a network of 11 pristine rivers draining the Australian Victorian Alps was collected at different locations during (i) high discharge (June 2006) and (ii) low discharge (February 2007) conditions and was analyzed for dissolved major ions, ?2H and ?18O, and ?34S of dissolved sulphate. River water chemistry implies that solutes are largely derived from precipitation and chemical weathering of silicate lithologies. Cl/Br ratios as low as 30 molar suggest that rivers have not dissolved halite, however, higher salinity (?100 mmol/L) winter samples have intermediate Cl/Br ratios (600 to 2000 molar) that are attributed to minor halite dissolution at the onset of the rainy season. Subsequent mixing of river water homogenizes ratios and evaporation is the dominant process that increases downstream salinities. Oxygen and Hydrogen isotopes also indicate that mixing and evaporation have occurred. Despite the lack of carbonate outcrops in the study area and uniform negative calcite saturation indices, the dissolution of hydrothermal calcite may account for up to 67% of the total dissolved cations, generating up to 92% of all dissolved Ca and Mg. The sulphur isotope data (16 to 20°CDT) indicates that the dissolved SO4 is derived predominantly from atmospheric deposition and minor gypsum weathering and not from bacterial reduction of FeS. This militates against sulphuric acid weathering in Victorian rivers. Si/(Na* + K*) ratios suggest that silicate weathering is dominated by the transformation of plagioclase (An40) to smectite and, to a lesser extend, the production of kaolinite. In total, chemical weathering consumes 17.6 x 106 (summer) to 71.59 x 106(winter) mol/km2/yr CO2, with the highest values in rivers draining the basement outcrops rather than sedimentary rocks. This range is at the upper end of the global scale and shows that the predominance of fresh silicate lithologies exerts the main control on higher CO2 fluxes; temperature and runoff, in turn, are crucial variables for the inter- seasonal variability in this region. Data on discharge and major ion chemistry, measured in regular intervals between 1977 and 1990, support this; however, the timing of absolute maxima of Si/(Na* + K*) and CO2 flux peaks do not coincide. We suggest that the combination of dissolution of diatoms that precipitated under low flow- and high temperature conditions in the tributaries and Na-adsorption by suspended clay particles, that were probably redistributed locally after bushfires and/or duststorms during drought periods in the early 1980's, as mechanisms to spontaneously elevate Si/(Na* + K*) ratios and, when coupled with irregular discharge fluctuations, explain deviations from seasonal CO2 fluxes.

Hagedorn, B.; Cartwright, I.

2007-12-01

204

Solutions to Avoid Red Tide, Inc.  

NSDL National Science Digital Library

This "Solutions to Avoid Red Tide" (START) webpage offers basic information and videos about red tide, effects of red tide, and research being done regarding red tide. START is a grassroots, non-profit organization based in Florida. Their mission is to keep federal, state, and local officials aware of red tide and to get these officials to fund projects to remediate and/or prevent the problem. Information on how to join or help START is also provided.

Solutions To Avoid Red Tide, Inc.

205

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)

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 findings are encouraging for the prospects of basin-scale ocean dynamical downscaling using a weather-typing approach to reconstruct forcing fields for high resolution ocean models (Part II) from coarse resolution climate models.

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

2011-01-01

206

Solar heating using the tide  

SciTech Connect

A fixed tank is disposed in the sea adjacent a floating solar still, with a flexible conduit extending between a lower portion of the tank and the interior of the still. A one-way check valve disposed in the lower portion of the tank permits sea water to enter the tank and fill it as the tide rises. As the tide lowers, water flows from the tank through a restriction in the conduit to the solar still.

Cardinal, D.E.

1980-04-08

207

Red Tide and Shellfish Poisoning  

NSDL National Science Digital Library

This EnviroFacts informational page discusses how red tide develops and how people might be affected by this phenomenon. It covers physical damage, oxygen depletion, direct poisoning, and indirect poisoning including paralytic shellfish poisoning (PSP), diarrhetic shellfish poisoning (DSP), neurotoxic shellfish poisoning (NSP), amnesiac shellfish poisoning (ASP), and aerosol toxins. The page concludes with a discussion of red tide and the role of the sea fisheries research institute.

Maneveldt, Gavin W.; Matthews, Sue; Pitcher, Grant; Van Der Vyver, Irma

2010-01-29

208

Solar weather/climate predictions  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

209

Weather Basics  

NSDL National Science Digital Library

Students are introduced to the basics of the Earth's weather. Concepts include fundamental causes of common weather phenomena such as temperature changes, wind, clouds, rain and snow. The different factors that affect the weather and the instruments that measure weather data are also addressed.

Integrated Teaching And Learning Program

210

Weather Forecasting  

NSDL National Science Digital Library

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

Integrated Teaching And Learning Program

211

Severe Weather  

NSDL National Science Digital Library

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, flash floods, lightning, and tornadoes.

Forde, Evan B.

2004-04-01

212

Severe Weather  

ERIC Educational Resources Information Center

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…

Forde, Evan B.

2004-01-01

213

Severe Weather  

ERIC Educational Resources Information Center

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,…

Forde, Evan B.

2004-01-01

214

Severe Weather  

NSDL National Science Digital Library

Meteorologists disagree as to what constitutes severe weather. However, most concur that thunderstorms, tornadoes, and hurricanes, all considered to be "convective" weather, fit the definition of severe weather, which is a weather condition likely to cause hardship. This science guide will explore each of the three weather phenomena. By virtue of their locations, most students are familiar with at least one of the three severe weather events. Students who tour the web sites will have an opportunity to make connections between the familiar and the perhaps less understood weather events.

National Science Teachers Association (NSTA)

2005-04-01

215

Tides and Modern Geodesy  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

216

Tides in Planetary Systems  

NASA Astrophysics Data System (ADS)

The Solar system is the seat of many interactions between the Sun, the planets and their natural satellites. Moreover, since 1995, a large number of extrasolar planetary systems has been discovered where planets orbit around other stars, sometimes very close to them. Therefore, in such systems, tidal interactions are one of the key mechanisms that must be studied to understand the celestial bodies' dynamics and evolution. Indeed, tides generate displacements and flows in planetary (and in the host star) interiors. The associated kinetic energy is then dissipated into heat because of internal friction processes. This leads to secular evolution of orbits and of spins with characteristic time-scales that are intrinsically related to the properties of dissipative mechanisms, those latters depending both on the internal structure of the studied bodies and on the tidal frequency. This lecture is aimed to review the must advanced theories to study tidal dynamics in planetary systems and the different tidal flows or displacements that can be excited by a perturber, the conversion of their kinetic energy into heat, the related exchanges of angular momentum, and the consequences for systems evolution.

Mathis, Stéphane; Le Poncin-Lafitte, Christophe; Remus, Françoise

217

Winter Weather  

NSDL National Science Digital Library

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

Bellows, Mrs.

2009-09-28

218

Red Tide off Texas Coast  

NASA Technical Reports Server (NTRS)

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

2002-01-01

219

Eliassen-Palm Fluxes of the Diurnal Tides from the Whole Atmosphere Community Climate Model-Extended (WACCM-X)  

NASA Astrophysics Data System (ADS)

Through perturbation interactions with the zonal mean flow, the migrating diurnal tide and the diurnal eastward 3 (DE3) tide are fundamental to a holistic understanding of the atmospheric dynamics at mesosphere lower thermosphere (MLT) and low ionospheric altitudes. Previous tidal studies have noted the semiannual variability associated with the migrating diurnal tide and the DE3 tide, which maximize around equinox and minimize around solstice. Seasonally varying source and dissipation regions and/or wind structures are believed to cause the differences in the maximum amplitudes experienced between the two equinoxes. Utilizing monthly averaged output from the Whole Atmosphere Community Climate Model-Extended (WACCM-X), this study is among the first to apply this model to a diagnostic examination of the sources and sinks of tidal momentum and document the associated seasonal variability. From the averaged amplitudes obtained during March and September, the WACCM-X replicates the observed seasonal variability associated with the migrating diurnal tide and the DE3 tide. Calculating the divergence of the Eliassen-Palm Flux (EP Flux) for the migrating diurnal tide revealed robust seasonal variation which may be linked to differential solar heating of ozone in the stratosphere. Seasonal variation in the tropospheric sources of the DE3 tidal momentum alone does not appear to explain the semiannual variability observed in the tidal amplitudes. This study provides a better understanding of the seasonal variation in the generation and dissipation mechanisms of the migrating diurnal tide and the DE3 tide.

Jones, M.; Liu, H.; Richmond, A. D.

2009-12-01

220

Precession, Tides and the Geodynamo  

NASA Astrophysics Data System (ADS)

It is a widely accepted hypothesis that buoyancy in the fluid core powers the geodynamo. Estimates of the available power rest on assumptions about the material properties of the core, its composition and its history. By contrast, we know with much better accuracy the rotational motion of the Earth and its tidal deformation. We are thus prompted to inquire what effects precession and tides have on the core flow. If precession and tides are neglected, fluid particles in the core revolve once a day about the geographic axis on a circular path. Both precession and tides distort the stramlines into ellipses. From theory, simulations and experiments, it is known that this deformation can trigger an instability. Whether this actually happens inside the Earth is presently uncertain because of our insufficient knowledge about core viscosity. Assuming precession indeed leads to instability in the core, simulations have shown that the resulting flow is a dynamo by itself. But precession and tides could also interact with a dynamo driven by buoyancy and leave an observable signature in magnetic secular variation. This is in particular expected if "resonant collapses" occur, a phenomenon in which the flow cyclically traverses laminar and chaotic phases. This presentation will give an overview of our present knowledge of flows driven by precession and tides and point to some open questions.

Tilgner, A.

2006-05-01

221

Observations of upper atmospheric weather during solar minimum winter  

SciTech Connect

The authors report on a wide variety of thermospheric and ionospheric observations from three consecutive January World Day campaign periods. Despite remarkably similar geophysical conditions characterizing the in situ forcing of the upper atmosphere during these solar minimum campaigns, they find significant variability in the observations of the ionosphere and thermosphere particularly at low latitudes in the American sector. In addition, they present further observational evidence of the unexpected exospheric temperature suppression at low latitudes initially reported by Hagran and Salah (1988). They discuss the lower and upper atmospheric coupling mechanisms of plausible importance to the interpretation of the observed thermospheric weather patterns. They report evidence that lower thermospheric (NO) (nitric oxide number density) and upward propagating atmospheric tides affected the thermospheric energy and momentum budgets during the campaign periods.

Hagan, M.E. (Massachusetts Inst. of Tech., Westford (United States) National Center for Atmospheric Research, Boulder, CO (United States)); Barth, C.A. (Univ. of Colorado, Boulder (United States)); Tobiska, W.K. (Univ. of California, Berkeley (United States)); Manson, A.H. (Univ. of Saskatchewan, Saskatoon (Canada)); Vincent, R.A. (Univ. of Adelaide (Australia)); Buonsanto, M.J. (Massachusetts Inst. of Tech., Westford (United States)); Burnside, R.G. (Cornell Univ., Arecibo (Puerto Rico)); Wickwar, V.B. (Utah State Univ., Logan (United States))

1992-04-01

222

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)

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 growing season. Results of this study indicate that the carbon cycle of forests in Great Lakes region in eastern North America is more affected by changes in temperature rather than variations in precipitation, unless dry conditions coincide with the short and intense early growing season of the region. This research helps to assess the vulnerability of managed forests to future climate change and extreme weather events.

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

2013-12-01

223

Weathering Animation  

NSDL National Science Digital Library

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

2002-01-01

224

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

PubMed

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

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

2014-08-01

225

Weather on the Nearest Brown Dwarfs: Resolved Simultaneous Multi-wavelength Variability Monitoring of WISE J104915.57-531906.1AB  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

226

Weather Forecasting  

NSDL National Science Digital Library

This website, supplied by Annenberg / CPB, discusses weather satellites, Doppler radar, and additional tools forecasters use to predict the weather. Students can find a wind chill calculator along with a brief discussion of the history of forecasting and weather lore. Once you have a firm grasp on the science of weather forecasting, be sure to check out the other sections of this site, which include: "ice and snow," "our changing climate," "the water cycle," and "powerful storms."

2008-03-27

227

Weather Talk  

NSDL National Science Digital Library

Weather Talk is a primer on weather and naval meteorology. It provides a brief overview of major weather elements and is presented in a non-mathematical way, so that the reader will have a better understanding of the basic mechanisms of weather and use it to their advantage and safety in planning and carrying out their own activities. The site explains temperature, wind, pressure, atmospheric moisture, air masses and fronts, thunderstorms, tornadoes, hurricanes, and climatology.

228

Antarctic Weather  

NSDL National Science Digital Library

Visitors to this site can read a discussion about the weather in Anarctica, including why it is so cold, how weather observations are conducted there, and what role the continent plays in the global weather system. Links to related topics, a wind chill calculator, and a Fahrenheit-Celsius-Kelvin temperature converter are also provided.

229

WWW Tide and Current Predictor  

NSDL National Science Digital Library

From the University of South Carolina's Wethey Lab Homepage, the tide and current predictor contains up-to-date basic predictions and a format for obtaining customized predictions. Access to data is organized by location. Location choices include US Upper East Coast (Maine through Virginia), US Lower East Coast (North Carolina through Florida Keys), US Gulf Coast sites (East to West), US West Coast sites (North to South), Northern sites (except Japan) outside contiguous US (East to West), Southern sites outside contiguous US (East to West), and Japan and nearby sites (North to South). Also, the site includes answers to FAQs concerning this tide predictor.

230

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

NASA Technical Reports Server (NTRS)

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

Ray, Richard D.

2009-01-01

231

Comparison of ocean tide models for accurate computation of ocean tide loading in Korean Peninsula  

NASA Astrophysics Data System (ADS)

We investigated the effects of different ocean tide models on the prediction of the ocean tide loading in Korean peninsula. The western part of Korean peninsula has large tidal range of water level and complicated rias coasts, so that accurate ocean tidal loading models are necessary for high-precise geodetic applications. The information of coastlines and the accuracy of the ocean tide model are key factors for high accurate ocean tide loading models. Recently, the global ocean tide models based on extensive observations and local tide models for the local area have been released. In this study, we analyzed the accuracy of ocean tide loadings with various ocean tide models. We developed a program for the convolutions of the mass of ocean tide and the load Green's functions. Comparing the computations with GOTIC2, the differences of vertical deformations due to M2 constituent were less than 0.4 mm in the case of the same ocean tide model. The five global ocean tide models, NAO99b, FES2004, DTU10, EOT11a and HAMTIDE, one regional tide model, NAO99Jb, and two local tide models were tested. The tests were performed in two ways. One was to use only global ocean tide models and the other one combined each global tide model and local tide model. Finally, we compared the computations with the GPS observations.

Baek, J.; Na, S.; Park, P.; Choi, B.; Cho, S.

2011-12-01

232

Earth Tides and Their Impact on Ocean Tide Prediction.  

National Technical Information Service (NTIS)

The problem of obtaining the solid earth's response to tidal forces is outlined in this extract from Tim Whorf's thesis. The thesis treats the problem of searching for a non-Newtonian gravitational effect in earth tides which is due to a fixed universal r...

R. A. Haubrich

1975-01-01

233

Weather at the L/T Transition: A Large J-Band Survey for Variability of Cool Brown Dwarfs  

NASA Astrophysics Data System (ADS)

An outstanding issue in the understanding of ultracool dwarf atmospheres is the abrupt shift from red (J-K ˜2) to blue (J-K ˜0) near-infrared colors, accompanied by a J-band brightening, at the boundary between L and T spectral types, marking the transition from cloudy to cloud-free atmospheres. While current 1-dimensional cloud models generally fail to capture the main features of the transition, most notably the narrow temperature range over which it occurs, it has been hypothesized that a disruption of the cloud layer as it sits progressively lower in the photosphere could contribute to a more abrupt decrease in dust opacity in this regime. If present, such patchy cloud coverage should give rise to photometric variability on rotational timescales. Motivated in part by the recent discovery of ˜50 mmag periodic variability of the T2 dwarf SIMP0136 by Artigau et al. 2009, we have undertaken the most comprehensive near-infrared variability survey of cool brown dwarfs to date, designed to test for heterogeneous cloud coverage in a sample of brown dwarfs spanning mid-L to late-T spectral types. Our J-band search has targeted 56 objects with high cadence, high precision, photometric sequences, and is complemented by follow-up observations in H and Ks bands to characterize the nature of the variations. Here we describe our large survey, and showcase the first, preliminary results. Our data set hints at a higher incidence of variability within the the L/T transition regime.

Radigan, J.; Jayawardhana, R.; Lafrenière, D.; Artigau, É.

2011-12-01

234

Nonmigrating tidal heating and MLT tidal wind variability due to the El Niño-Southern Oscillation  

NASA Astrophysics Data System (ADS)

Tides forced by large-scale weather systems in the tropical troposphere introduce significant longitudinal and local time variability in the upper atmosphere. This paper presents variability of tidal harmonics of the latent heating from 2002 to 2011 associated with the El Niño-Southern Oscillation (ENSO) and the tidal wind response in the mesosphere/lower thermosphere (MLT) region. Emphasis is on the strong ENSO cycle 2009-2011. Latent tidal heating rates are computed from TRMM satellite precipitation data, with added radiative heating from MERRA reanalysis, as functions of time, latitude, and altitude. The heating rates for the two most affected nonmigrating tides (DE3 and DE2) are examined and compared with MLT tidal wind variability from TIDI/TIMED. Principal component analysis (PCA) is used to identify the tidal modes most affected by ENSO. Our results indicate that the tidal response to ENSO is largest during winter for both of the tides, with the largest response occurring in the DE3 tidal winds during the La Niña phase, with an increase of roughly 70% for the winter months of 2010/2011, and negligible response during the El Niño phase. The ENSO effect in the tidal forcing closely resembles the first symmetric and antisymmetric Hough modes of DE3 and DE2, thus being an efficient mechanism to transmit the ENSO signal into the MLT tides.

Warner, K.; Oberheide, J.

2014-02-01

235

Awaiting High Tide to Set Block Nets  

USGS Multimedia Gallery

Sampling fish within the intertidal zone of a mangrove forest requires setting a block net at the interface between forest and river at high tide, then retrieving the net at low tide.  Here researchers await high tide to set the nets seen in the boat. ...

2010-08-13

236

NOAA New England Red Tide Information Center  

NSDL National Science Digital Library

This NOAA website offers a brief explanation of red tide and a large bloom that spread from the Gulf of Maine to the Massachusetts Bay in 2005. The site explains NOAA's efforts to remediate red tide in New England as well as prevent new occurrences. The site features hyperlinks to research funding, legislation, and other NOAA sites that feature red tide.

237

World Weather  

NSDL National Science Digital Library

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

Elias, Jaume S.

2014-02-20

238

Weather Watcher  

NSDL National Science Digital Library

As spring progresses, weather conditions can continue to fluctuate dramatically, something that may foil vacation plans or other outings. Keeping that in mind, visitors may do well to download the Weather Watcher application created by Mike Singer. With this application, users may automatically retrieve the current weather conditions, look through hourly forecasts, keep abreast of severe weather alerts, and take a look at weather maps for almost any city world-wide. This application is compatible with all systems running Windows 98 and above.

Singer, Mike

239

Mathematical modelling of global interaction between ocean tides and earth tides  

Microsoft Academic Search

Solid Earth deformation due to ocean tides gives rise to an essential interaction between ocean tides and Earth tides. A hydrodynamical-numerical 4°-ocean tide model has been generalized by including this interaction, which depends on gravitational attraction and loading effects. The resulting integro-differential equation system has been solved numerically for semidiurnal and diurnal tides. In this way global maps have been

Wilfried Zahel

1980-01-01

240

Auroral effects on midlatitude semidiurnal tides  

SciTech Connect

The effect of auroral activity on mid-latitude semidiurnal tides was investigated using simulations from the NCAR Thermosphere/Ionosphere General Circulation Model (TIGCM). Model runs were made for solar cycle minimum equinox conditions for four levels of geomagnetic activity parameterized by the total hemispheric power index and the cross polar cap potential drop. Simulations at 42.5{degree}N (gg) predicted that the upper thermosphere semidiurnal winds and temperatures generally increase with increasing geomagnetic activity, while the lower thermosphere fields were relatively insensitive to the level of auroral forcing in the model. The modeled semidiurnal mid-latitude tidal response was determined by the magnitude and phasing of the waves generated by in situ solar forcing and the auroral momentum and energy sources, in conjunction with those propagating up from the lower atmosphere. The predicted sensitivity of the model tides to the level of geomagnetic activity may contribute to the observed tidal variability at mid latitudes. Successful modeling of observations will require careful specification of the high-latitude energy and momentum sources.

Fesen, C.G. (Dartmouth Coll., Hanover, NH (United States)); Richmond, A.D.; Roble, R.G. (National Center for Atmospheric Research, Boulder, CO (United States))

1991-03-01

241

The magnetic tides of Honolulu  

USGS Publications Warehouse

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.

Love, Jeffrey J.;Rigler, Erin Joshua.

2013-01-01

242

WWW Tide and Current Predictor  

NSDL National Science Digital Library

This web page is a tide and current predictor provided by Dean Pentcheff from the University of South Carolina. The site allows you to select a region, choose the location, and then prepare a customized table of tidal height and/or current speed and direction.

Pentcheff, Dean

243

Nonlinear channel theory of tides.  

National Technical Information Service (NTIS)

This work is based on the constructive existence proof of solutions of nonlinear free boundary value problems of plane hydrodynamics given by E. Zeidler and a general computational method given by the author. The nonlinear channel theory of tides in an eq...

N. Moussa

1995-01-01

244

The magnetic tides of Honolulu  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

245

Middle and upper thermosphere density structures due to nonmigrating tides  

NASA Astrophysics Data System (ADS)

Density measurements from the SETA satellites near 200 km during 1982-1984, and the CHAMP and GRACE satellites between 350 and 550 km during 2002-2009, are used to investigate longitudinal structures in density due to nonmigrating tides, and to evaluate performance of the recently-created Climatological Tidal Model of the Thermosphere (CTMT). Amplitudes for the diurnal and semidiurnal tidal components fall roughly in the range of 4-10%. Diurnal tides at middle and low latitudes are often characterized by wave-3 and/or wave-4 structures, consistent with the presence of the eastward-propagating diurnal tides with zonal wave numbers s = 2 and s = 3 (DE2 and DE3, respectively) and with expected seasonal variability based on previous works. Semidiurnal structures often reflect the presence of the eastward-propagating tide with s = 2 (SE2), which gives rise to wave-4 structures that have a more antisymmetric relationship between N. and S. hemispheres. Similarities in structures between different years underscore the fact that the thermosphere is subject to repeatable and reproducible forcing by upward-propagating tides, but there are also occasions where considerable departures from climatology occur. Wave-2 structures at high latitudes likely contain signatures of the eastward-propagating diurnal tide with s = 1 (DE1) and the zonally-symmetric (s = 0) semidiurnal oscillation (S0) propagating upwards from below, but these and other waves that produce wave-2 can also be forced in-situ by high-latitude processes. The CTMT captures the salient features of the observations at middle and low latitudes, although with lower amplitudes that are likely due to phase cancelation effects resulting from averaging over multiple years (2002-2006). We propose that some discrepancies between the CTMT and our observational results may be associated with wave components arising in-situ in the thermosphere as the result of nonlinear tide-tide interactions and plasma neutral interactions, the latter being especially prominent at high latitudes where the displaced geomagnetic frame is particularly influential. Modeling studies are required to validate these proposed mechanisms, however.

Forbes, Jeffrey M.; Zhang, Xiaoli; Bruinsma, Sean

2012-11-01

246

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)

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 ?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 ?m, while 4.5 ?m Spitzer observations yield a 4.5 ?m/3.6 ?m amplitude ratio of only 0.23 ± 0.15, consistent with zero 4.5 ?m variability. This wide range in amplitudes indicates rotationally modulated variability due to magnetic phenomena and/or inhomogeneous cloud cover. Weak H? 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 ~3? 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.

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

247

Weather Instruments  

NSDL National Science Digital Library

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

248

Predicting Weather  

NSDL National Science Digital Library

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

2008-03-28

249

Weather Experiments  

NSDL National Science Digital Library

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

2010-01-01

250

Space weather  

NASA Astrophysics Data System (ADS)

Space weather is caused by conditions on the Sun and in the solar wind, the magnetosphere, ionosphere and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and can affect human life or health. It affects man-made systems such as satellite electronics, terrestrial power grids and radio communications. This paper provides an overview of how space weather arises in the solar terrestrial system and how physical processes are able to cause space weather effects. We also discuss European perspectives and activities geared towards the possible initiation of a European Space Weather programme.

Glover, Alexi; Daly, Eamonn; Hilgers, Alain; Berghmans, David

2002-05-01

251

Nonmigrating diurnal tides in the equatorial middle atmosphere  

SciTech Connect

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.

Lieberman, R.S.

1992-01-01

252

Estimating Tides from a Planetary Flyby Mission  

NASA Astrophysics Data System (ADS)

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 instrument performance (frequency, maximum range, measurement noise) and an artificial topographic map of the surface. These simulated data are processed using perturbed initial states, and batched least-squares estimation yield estimated values and uncertainties for selected parameters. Preliminary results with Ka-band radiometric data alone suggest the Love number k2 can be recovered to about 1 percent with this flyby tour trajectory. Altimetric crossovers are to be constructed and used to constrain the deformational tidal Love number h2. The number, and impact, of available crossovers strongly depends on the capability of the laser altimeter, and we quantify how a larger maximum range can contribute to the recovery of the body tide.

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

2014-05-01

253

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)

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 studied watersheds may sometimes remain very similar with a homogeneous rainfall input, whereas for some cases the differences in the peak discharges can reach up to 80%. A detailed analysis illustrates the possible role of the watershed in enhancing the effect of rainfall spatial variability. In a further step, the objective is to test the ability of four rainfall variability indicators to identify the situations for which spatial rainfall variability has the greatest influence on the watershed response. The selected indicators include those of Zoccatelli et al. (2010), and all rely on a detailed analysis of spatial rainfall organization in function of hydrological distances (i.e. the distances measured along the stream network from one point of the watershed to the outlet). The analysis of the links between these indicators and the hydrological behaviors identified is currently in progress. Reference: Naulin, J.P., Payrastre, O., Gaume, E., 2013. Spatially distributed flood forecasting in flash flood prone areas: Application to road network supervision in Southern France. Journal of Hydrology, 486, 88-99, doi:10.1016/j.jhydrol.2013.01.044 Zoccatelli, D., Borga, M., Zanon, F., Antonescu, B., Stancalie, G., 2010. Which rainfall spatial information for flash flood response modelling? A numerical investigation based on data from the Carpathian range, Romania. Journal of Hydrology, 394, 148-161

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

2014-05-01

254

Influence analysis of Arctic tide gauges using leverages  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

255

The tides of Titan.  

PubMed

We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k(2) = 0.589 ± 0.150 and k(2) = 0.637 ± 0.224 (2?). Such a large response to the tidal field requires that Titan's interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth. PMID:22745254

Iess, Luciano; Jacobson, Robert A; Ducci, Marco; Stevenson, David J; Lunine, Jonathan I; Armstrong, John W; Asmar, Sami W; Racioppa, Paolo; Rappaport, Nicole J; Tortora, Paolo

2012-07-27

256

Stratospheric Tides and Data Assimilation  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

257

Tide following wave power machine  

SciTech Connect

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.

Murphy, J.T.

1982-09-21

258

Lunar tides in Loch Ness, Scotland  

NASA Astrophysics Data System (ADS)

Measurements have been made of the astronomical tide in Loch Ness, Scotland, which is not directly connected to marine tides. Our measurements of the loch tide are, so far as we know, the first in a European lake where the tide originates primarily from ocean tide loading. Loch Ness is a readily accessible lake and is in a region for which the neighboring ocean tides are large and described well by modern global ocean tide models. The principal tidal constituent, M2, was observed to have an amplitude of approximately 1.5 mm, and to be in antiphase, at each end of the loch. These values are in close agreement with the theoretical combined effects of the direct gravitational tide (body tide) and the tilt effects due to ocean tide loading, computed using Green's functions based on conventional elastic-Earth models. By analyzing over long periods for coherent tidal signals, we are able to significantly improve the signal-to-noise ratio in the tilt values compared with values obtained by direct level differencing. Our tilt accuracy of better than 10-8, measured over 35 km, demonstrates Loch Ness as one the world's longest and most accurate tiltmeters. Despite this unprecedented accuracy, Earth tidal models are still at least as accurate as our ability to measure them.

Pugh, David T.; Woodworth, Philip L.; Bos, Machiel S.

2011-11-01

259

The magnetic tides of Honolulu  

NASA Astrophysics Data System (ADS)

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.

Love, Jeffrey J.; Rigler, E. Joshua

2014-06-01

260

Toxic Blooms: Understanding Red Tides  

NSDL National Science Digital Library

This online seminar reviews the topic of red tides in four sessions, which review the effect HABs have on public health, wildlife and the economy; describe common harmful algal species and their toxins; identify poisoning symptoms; compare methods of treatment if poisoned; describe some potential methods to control HABs; and identify research areas where information on HABs is still inadequate. After completing the sessions, an optional knowledge test is provided based on the seminar material.

Anderson, Don; The Woods Hole Oceanographic Institution, Fathom

261

Ocean Tides Lost and Found  

NSDL National Science Digital Library

The Moon's gravity imparts tremendous energy to the Earth, raising tides throughout the global oceans. What happens to all this energy? Scientists studying data from the orbiting TOPEX/Poseidon satellite believe they now have an answer. Users can read about the tidal energy imparted upon the earth by the Moon and where scientists believe it is dissipated, and view animations that show these effects.

262

The magnetic tides of Honolulu  

NASA Astrophysics Data System (ADS)

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.

Love, Jeffrey J.; Rigler, E. Joshua

2014-04-01

263

Weather Forecasting  

NSDL National Science Digital Library

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

Twin Cities Public Television, Inc.

2005-01-01

264

Space Weather  

NASA Technical Reports Server (NTRS)

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.

Gallagher, Dennis L.

2010-01-01

265

Weather Instruments.  

ERIC Educational Resources Information Center

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…

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

266

Low-tide rainfall effects on metal content of suspended sediment in the Sacramento-San Joaquin Delta  

NASA Astrophysics Data System (ADS)

Rain falling at or near low tide is capable of eroding and transporting cohesive sediment from intertidal areas. Given that metals adsorb strongly to silt- and clay-sized particles, it is conceivable that low-tide rainfall may also liberate previously-deposited metals from storage in intertidal sediment. To investigate the potential for rainfall as an agent of remobilization, this study tested the hypothesis that suspended sediment in a tidal creek during low tide rainfall events contains different suites of adsorbed metals than during wind-only events and fair weather days. Water samples were collected during low-tide rain events in winter and wind resuspension events in summer. The concentrations of suspended sediment, particulate organic carbon and nitrogen, and the total adsorbed concentration (g L-1) of most metals were higher for a low-tide rainfall event than during wind-only and fair-weather conditions. Metal contents (g g-1) were also greater during the rain event for most metals. Principal components analysis and relationships between metal content and suspended sediment concentration suggest that rainfall during low tide can mobilize a different source of sediment than wind-wave resuspension and regular tidal action. The metal content of bulk sediment samples from around the study area could not be matched satisfactorily to the suspended sediment in any of the events. This implies that bulk sediment composition should not be used to extrapolate to suspended sediment composition in terms of adsorbed metal content.

Moskalski, Susanne M.; Torres, Raymond; Bizimis, Michael; Goni, Miguel; Bergamaschi, Brian; Fleck, Jacob

2013-03-01

267

The pole tide in deep oceans  

NASA Technical Reports Server (NTRS)

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.

Dickman, S. R.

1990-01-01

268

Weather Forecasting  

NSDL National Science Digital Library

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

Nielsen-Gammon, John

1996-09-01

269

The Tides of Titan  

NASA Astrophysics Data System (ADS)

Titan has long been thought to host a subsurface water ocean. A liquid water or water-ammonia layer underneath the outer icy shell was invoked to explain the Voyager and Cassini observations of abundant methane (an easily dissociated species) in the atmosphere of the satellite. Given the paucity of surface hydrocarbon reservoirs, the atmospheric methane must be supplied by the interior, and an ocean can both provide a large storage volume and facilitate the outgassing from the deeper layers of the satellite to the surface. Huygens probe observations of a Schumann-like resonance point to the presence of an electrically conductive layer at a depth of 50-100 km, which has been interpreted to be the top of an ammonia-doped ocean [1]. Cassini gravity observations provide stronger evidence of the existence of such subsurface ocean. By combining precise measurements of the spacecraft range rate during six flybys, suitably distributed along Titan's orbit (three near pericenter, two near apocenter one near quadrature), we have been able to determine the k2 Love number to be k2 = 0.589±0.150 and k2 = 0.637±0.224 in two independent so-lutions (quoted uncertainties are 2-sigma) [2]. Such a large value indicates that Titan is highly deformable over time scales of days, as one would expect if a global ocean were hidden beneath the outer icy shell. The inclusion of time-variable gravity in the solution provided also a more reliable estimate of the static field, including an updated long-wavelength geoid. We discuss the methods adopted in our solutions and some implications of our results for the interior structure of Titan, and outline the expected improvements from the additional gravity flybys before the end of mission in 2017. [1] C. Beghin, C. Sotin, M. Hamelin, Comptes Rendue Geoscience, 342, 425 (2010). [2] L. Iess, R.A. Jacobson, M. Ducci, D.J. Stevenson, J.I. Lunine, J.W. Armstrong, S.W. Asmar, P. Racioppa, N.J. Rappaport, P. Tortora, Science, 337, 457 (2012).

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

2012-12-01

270

Meteor radar observations of short-term variability of quasi 2 day waves and their interaction with tides and planetary waves in the mesosphere-lower thermosphere region over Thumba (8.5°N, 77°E)  

NASA Astrophysics Data System (ADS)

Meteor radar measurements of zonal and meridional winds over a low-latitude station, Thumba (8.5°N, 77°E), during March 2006 to March 2009 are used to study the quasi 2 day wave structure in the mesosphere-lower thermosphere (MLT) region. Emphasis is placed on the study of the day-to-day variations of quasi 2 day waves and their interaction with diurnal tides and planetary waves. The seasonal variation of quasi 2 day waves showed two maxima, one during summer and the other during winter, coinciding with the strong eastward winds in the MLT region along with a distinct peak during the month of October. Subsequent analysis of TIMED/SABER observations during October revealed the presence of a westward propagating quasi 2 day wave with zonal wave number 3 over the present latitude. The seasonal variation of quasi 2 day wave is also discussed with respect to the Stratospheric Semiannual Oscillation (SSAO), and we found that the quasi 2 day wave activity peaks in the MLT region during the phase transition of SSAO as well as during the eastward phase. Wavelet and subsequent bispectral analysis confirmed the wave-wave interactions of quasi 2 day wave and planetary waves with periods of 5-10 and 15-20 days. The 16 h oscillation, which is believed to be generated by interaction of quasi 2 day wave and diurnal tide, showed an excellent correlation with quasi 2 day wave activity. Apart from reporting day-to-day variation of quasi 2 day wave for the first time over this latitude, there are two new results from the present study: (1) a consistent peak in quasi 2 day activity during October, which has never been reported and has been observed for the first time over low latitudes, and (2) the relation between SSAO and quasi 2 day wave activity.

Suresh Babu, Veena; Kishore Kumar, Karanam; John, Sherine R.; Subrahmanyam, K. V.; Ramkumar, Geetha

2011-08-01

271

Planetary Weather  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on the weather conditions on other planets. After learning more about weather patterns, students research the weather on a given planet and create a visual display of the conditions there. It includes objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

272

Tide effects removed from well tests  

SciTech Connect

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.

Aase, E.P.B.; Jelmert, T.A. [Norwegian Inst. of Technology, Trondeim (Norway); Vik, S.A. [Saga Petroleum A.S., Sandvika (Norway)

1995-05-01

273

New aspects of the equilibrium pole tide  

NASA Technical Reports Server (NTRS)

A new spherical harmonic algorithm is developed for the calculation of the loading and self-gravitating equilibrium pole tide. Based on a suggestion of Dahlen (1976), this approach minimizes the distortions in tide height caused by an incomplete representation of the ocean function. With slight modification this approach easily could be used to compute self-gravitating and loading lunisolar tides as well. Using the algorithm, the static pole tide is compared with tide observations at a variety of locations around the world, and statistically significant evidence for pole tide enhancements is found in midocean as well as the shallow seas. Also included is a reinvestigation of the effect of the static tide on the Chandler-wobble period. The difference between the wobble period of an oceanless elastic earth with a fluid core (Smith and Dahlen, 1981) and the period of an earth minus static oceans yields a 7.4-day discrepancy. It is concluded from tide observations that much of the discrepancy can probably be accounted for by nonequilibrium pole-tide behavior in the deep oceans.

Dickman, S. R.; Steinberg, D. J.

1986-01-01

274

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

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.

Heinze, Aren N.; Metchev, Stanimir [Department of Physics and Astronomy, State University of New York, Stony Brook, NY 11794-3800 (United States); Apai, Daniel; Flateau, Davin [University of Arizona Department of Astronomy, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Kurtev, Radostin [Departamento de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile); Marley, Mark [NASA Ames Research Center, MS-245-3, Moffett Field, CA 94035 (United States); Radigan, Jacqueline [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Burgasser, Adam J. [University of California San Diego, Center for Astrophysics and Space Science, 9500 Gilman Drive, Mail Code 0424, La Jolla, CA 92093 (United States); Artigau, Etienne [Departement de Physique and Observatoire du Mont Megantic, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, QC, H3C 3J7 (Canada); Plavchan, Peter, E-mail: aren.heinze@stonybrook.edu, E-mail: stanimir.metchev@stonybrook.edu [NASA Exoplanet Science Institute, California Institute of Technology, M/C 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

2013-04-20

275

Weatherizing America  

ScienceCinema

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

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

2013-05-29

276

Weather One  

NSDL National Science Digital Library

This website contains summaries and lessons about various aspects of weather. This includes the seasons, types of clouds, air, winds, global warming, hurricanes, tornadoes and lightning. Worksheets are provided to accompany the lesson themes.

Friend, Duane

277

Weather Watchers  

NSDL National Science Digital Library

In this month-long interdisciplinary project students collect weather data, determine the best visual representation for displaying it, and discuss the patterns and implications of their findings. This resource includes extension and assessment suggestions and guiding questions.

2014-01-01

278

Weatherizing America  

ScienceCinema

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

279

Space Weather  

NASA Astrophysics Data System (ADS)

Following James Van Allen's discovery of Earth's radiation belts (1958), it was immediately recognized that the space environment would be hostile to the communications satellites that had been envision by Arthur Clark (1945) and John Pierce (1955). Van Allen's discovery set off a burst of "space weather" research and engineering that continues to today, paralleling "space weather" research that had, prior to 1958, been directed toward understanding environment effects on cable and early wireless communications, electric power distribution, and pipelines. Van Allen's discovery also meant that the flight of humans above the sensible atmosphere would be fraught with more peril than mere weightlessness. This Van Allen lecture will discuss the space weather considerations that arose from Van Allen's discovery as well as space weather effects that occur from numerous other physical processes in the complex sun-heliosphere-magnetosphere environmental system.

Lanzerotti, L. J.

2005-05-01

280

Weatherizing America  

SciTech Connect

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

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

2009-01-01

281

Mapping low-mode internal tides near Hawaii using TOPEX/POSEIDON altimeter data  

NASA Astrophysics Data System (ADS)

Objective maps of M2 internal-tide variability are derived from TOPEX/POSEIDON altimeter data obtained near the Hawaiian Ridge. An estimate of the wavenumber spectrum shows that the radiation is dominated by a few spectral peaks at wavenumbers consistent with the theoretically expected value for mode-1 internal tides. The data are not always consistent with the traveling wave model. Because the spacing of the altimeter tracks is larger than the internal-tide wavelength, the objective map underestimates the energy between the altimeter tracks. With this caveat, the maps are used to determine that 2.6 GW of power is radiated from a 1700 km section of the Hawaiian Ridge. Time series of hydrographic data obtained at the HOT site north of Oahu, Hawaii show that changes in mode-1 phase speed, caused by variations in stratification, have only a small effect on the propagation of the mode-1 internal tides.

Dushaw, Brian D.

2002-04-01

282

Weathering Experiment  

NSDL National Science Digital Library

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

Stelling, Pete

283

Weather Creator  

NSDL National Science Digital Library

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

Kshumway

2009-09-28

284

Weather Maps  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades K-5. It focuses on basic information about the weather and how different weather maps depict conditions. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

285

About Water Levels, Tides & Currents  

NSDL National Science Digital Library

The Oceanographic Products and Services Division (OPSD) of the National Oceanic and Atmospheric Administration (NOAA) "collects, analyzes and distributes historical and real-time observations and predictions of water levels, coastal currents and other meteorological and oceanographic data." This wonderful site explains the science behind the tides and changing water levels, gives historical background on tidal predictions and tidal machines (including several fascinating old photographs), and details the challenges of measuring water currents. The combination of engineering, history, and oceanography ensures that students and educators will learn much here. For access to tidal data, a tidal and current glossary, and an interactive tidal prediction page, users may follow links from the OPSD homepage.

2007-11-28

286

Public Perceptions of Florida Red Tide Risks  

PubMed Central

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.

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

2009-01-01

287

Nonmigrating diurnal tides in the thermosphere  

Microsoft Academic Search

Horizontal wind measurements from the HRDI and WINDII instruments on the Upper Atmosphere Research Satellite are analyzed to reveal the most prominent nonmigrating diurnal tidal components at 95 km: the eastward propagating diurnal tide with zonal wave number s = 3 (DE3), the standing (s = 0) diurnal oscillation (D0), and the westward propagating diurnal tide with s = 2

Jeffrey M. Forbes; Xiaoli Zhang; Elsayed R. Talaat; William Ward

2003-01-01

288

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

NASA Technical Reports Server (NTRS)

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.

Ray, Richard D.; Byrne, Deidre A.

2010-01-01

289

The Art of Red Tide Science.  

PubMed

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

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

2012-05-01

290

The Art of Red Tide Science  

PubMed Central

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.

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

2012-01-01

291

Space Weather  

NASA Astrophysics Data System (ADS)

This volume provides a comprehensive overview of our current observational knowledge, theoretical understanding, and numerical capability with regard to the phenomena known as space weather. Space weather refers to conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems, and can endanger human life or health. The rapid advance in these technologies has provided us with unprecedented capability and convenience, and we have come to rely on them more and more. Technology has reduced society's risk to many kinds of natural disasters, but through its own vulnerability, it has actually increased society's risk to space weather. Adverse conditions in the space environment can cause disruption of satellite operations, communications, navigation, and electric power distribution grids, leading to a variety of socioeconomic losses.

Song, Paul; Singer, Howard J.; Siscoe, George L.

292

Wild Weather  

NSDL National Science Digital Library

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

293

Weather Forecasting  

NSDL National Science Digital Library

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

2010-01-01

294

Weather One  

NSDL National Science Digital Library

From the University of Illinois Extension comes the Weather One instructional Web site for kids. The lesson consists of six pages that cover various weather related topics including seasons, clouds, the atmosphere, wind, global warming, and storms. Each page describes the particular subject, provides related photographs, and contains several activities that reinforce the learning. For example, the clouds page shows how kids can make a cloud and create a collage out of simple material found around the house. The effective organization and clean look of the site will surely make it easy for students to follow and enjoy.

1969-12-31

295

Space Weather  

NSDL National Science Digital Library

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

2004-02-06

296

Weather Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. Why does the wind blow? 2. When winds are blowing, how can you get them to stop? 3. What happens when the temperature is the same? 4. What happens when there is high relative humidity? 5. What ...

missy.jones@gmail.com

2009-09-28

297

Mapping of Tide and Tidal Flow Field Along a Tidal Creek With Vessel-based Observations  

NASA Astrophysics Data System (ADS)

Vessel-based acoustic Doppler current profilers (ADCPs) have long been used to measure only velocity profiles in numerous applications. In the present study, a vessel-towed ADCP is used to obtain data to infer both the tidal flow and tidal elevation along the Okatee Creek, South Carolina. This is an area surrounded by extensive coverage of inter-tidal salt marsh. A small vessel towing the ADCP repeatedly occupies a 10 km track meandering through the system within a complete tidal cycle during both neap and spring tides. While the velocity profiles are used to infer relevant harmonic constants, the water depth recorded by the four beams of the ADCP is used to extract the harmonic constants of the tidal elevation as well as the mean water depth. The phase difference between tidal elevation and velocity provides a more complete picture of the tide. In our study, the phase difference is found to be about 95 degree, indicating a standing tidal wave condition. Tidal amplitude is found to have relatively small variation along the creek while the velocity amplitude decreases significantly upstream, indicating a strong frictional attenuation. Statistical analysis demonstrates that higher percentage of variabilities of elevation and velocity can be explained during spring tides than neap tides: tidal signals during spring tides are not only stronger but also ``purer" or having less spread in the energy spectrum. The analysis also shows that higher percentage of variabilities are explained at the given tidal frequencies for the along channel velocity than for the cross channel velocity: the along channel velocity is ``purer" than the cross channel velocity. When only a M2 and mean components are included in the harmonic analysis, about 65% and 82% of the covered area along the ship track, during neap and spring tides respectively, have ``good fit" for elevation: 60% or more of the variability at a given location can be explained by the tidal and mean components. By adding the M4 component in the harmonic analysis, an additional 6% and 2% of the covered area have ``good fit" for elevation for neap and spring tides, respectively. For the velocity field, similar conclusions hold except that by adding the M4 component an additional 12% of the covered area has ``good fit" for the neap tide data, in contrast to an improvement of only 2% for the spring tide data. The methodology presented here can be applied in tidal creek systems and channel systems of estuarine environment to obtain high -resolution distribution of tide and velocity field and to validate fine grid numerical models.

Li, C.; Blanton, J. O.

2002-05-01

298

Putting Weather into Weather Derivatives  

NASA Astrophysics Data System (ADS)

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

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

2001-12-01

299

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

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

300

Possible forcing of global temperature by the oceanic tides  

PubMed Central

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.

Keeling, Charles D.; Whorf, Timothy P.

1997-01-01

301

Possible forcing of global temperature by the oceanic tides.  

PubMed

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

Keeling, C D; Whorf, T P

1997-08-01

302

Weather Stations  

NSDL National Science Digital Library

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

303

Wonderful Weather  

NSDL National Science Digital Library

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

Workshop, Mission S.

2013-01-01

304

Today's Weather  

NSDL National Science Digital Library

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

305

Weather Wordsearch  

NSDL National Science Digital Library

Find the 12 weather related words in this word search brought to you by the Southeast Regional Climate Center (SERCC). When you finish finding all 12 words, hit the restart button to re-scramble the letters and start all over again!

2007-01-01

306

Pole tide in the Baltic Sea  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

307

The Weather Doctor  

NSDL National Science Digital Library

Published by Spectrum Educational Enterprises, The Weather Doctor Web site is maintained by meteorologist Keith Heidorn. Visitors to the site will find everything from the joys of weather watching, to making rain, to weather history, to much more. Coming from someone who clearly enjoys what they do, this site explores unique aspects of weather including weather people, weather history, and weather and arts.

Heidorn, Keith.

2002-01-01

308

Florida Red Tide Perception: Residents versus Tourists  

PubMed Central

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.

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

2010-01-01

309

Investigation on empirical estimation of minor tides  

NASA Astrophysics Data System (ADS)

In general recent global ocean tide models provide tidal constants for the most dominant semi-diurnal, diurnal, selected shallow water and some long period tides, typically M2, N2, N2 , K2, 2N2, O1 , P1 , Q1 , K1, S1, M4, Mf and Mm. Contributions of minor tidal terms and modulations of the main terms are in general considered by inferring admittance assumptions and nodal corrections. The rather new hydrodynamic model FES2012 extends this list and now provides additional tables for tidal constants for some 18 complementary minor tides. We investigate here if the long time series of precise multi-mission altimeter data (e.g. on the repeated ground tracks of TOPEX/Jason1/Jason2) allows a robust empirical estimation of those minor tides which appear to be (after the major tides listed above) the next dominant tidal waves. Candidate minor tidal waves are M1, J1, ?1, ?2, L2, T2, ?2. Can these partial tides empirically separated from tides with adjacent frequencies (e.g. ?2 versus 2N2 or T2 versus S2)? How do the tidal constant for those minor tides compare with those of the hydrodynamic model FES2012? What are the quantitative differences between applying admittance theory and using the tidal constants derived empirically? These investigations are performed in the context of the SPOT-project, aiming to improve the transfer function from ocean tide angular momentum to Earth rotation parameters, the variations of polar motion and LOD.

Bosch, Wolfgang; Madzak, Matthias; Hagedorn, Jan; Schuh, Harald; Böhm, Sigrid

2014-05-01

310

Ocean tides from Seasat-A  

NASA Technical Reports Server (NTRS)

Two procedures for the evaluation of global tides from SEASAT-A altimetry data are elaborated: an empirical method leading to the response functions for a grid of about 500 points from which the tide can be predicted for any point in the oceans, and a dynamic method which consists of iteratively modifying the parameters in a numerical solution to Laplace tide equations. It is assumed that the shape of the received altimeter signal can be interpreted for sea state and that orbit calculations are available so that absolute sea levels can be obtained.

Hendershott, M. C.; Munk, W. H.; Zetler, B. D.

1974-01-01

311

Diurnal tides in the Arctic Ocean  

NASA Technical Reports Server (NTRS)

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.

Kowalik, Z.; Proshutinsky, A. Y.

1993-01-01

312

NOAA Weather Radio Hourly Weather Roundup Formatter.  

National Technical Information Service (NTIS)

The National Weather Service (NWS) is planning to replace the aging National Oceanic and Atmospheric Administration (NOAA) Weather Radio (NWR) as part of its modernization program. The Office of Meteorology (OM) selected the Hourly Weather Roundup (HWR) t...

G. F. Battel G. A. Kokolis J. E. Calkins

1994-01-01

313

Weather Watchers  

NSDL National Science Digital Library

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

Integrated Teaching And Learning Program

314

Weather Cycles  

NSDL National Science Digital Library

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

Mitchell, Mrs.

2010-09-23

315

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

NASA Technical Reports Server (NTRS)

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.

Mayr, Hans G.; Mengel, John G.

2004-01-01

316

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

NASA Technical Reports Server (NTRS)

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.

Mayr, Hans G.; Mengel, John G.

2004-01-01

317

Observations of the internal tide on the California continental margin near Monterey Bay  

NASA Astrophysics Data System (ADS)

Observations of the semidiurnal internal tide on the California continental margin between Monterey Bay and Point Sur confirm the existence of northward energy flux predicted by numerical models of the region. Both a short-duration tide-resolving survey with expendable profilers and a multi-week timeseries from FLIP measured northward flux in the mean, supporting the hypothesis that topographic features off Point Sur are the source of the strong internal tides observed in Monterey Canyon. However, the observed depth-integrated semidiurnal flux of 450±200 W m-1 is approximately twice as large as the most directly-comparable model and FLIP results. Though dominated by low modes with O(100 km) horizontal wavelengths, a number of properties of the semidiurnal internal tide, including kinetic and potential energy, as well as energy flux, show lateral variability on O(5 km) scales. Potential causes of this spatial variability include interference of waves from multiple sources, the sharp delineation of beams generated by abrupt topography due to limited azimuthal extent, and local generation and scattering of the internal tide into higher modes by small-scale topography. A simple two-source model of a first-mode interference pattern reproduces some of the most striking aspects of the observations.

Terker, Samantha R.; Girton, James B.; Kunze, Eric; Klymak, Jody M.; Pinkel, Robert

2014-07-01

318

Weathering Corruption  

Microsoft Academic Search

Could bad weather be responsible for U.S. corruption? Natural disasters create resource windfalls in the states they strike by triggering federally provided natural-disaster relief. By increasing the benefit of fraudulent appropriation and creating new opportunities for such theft, disaster-relief windfalls may also increase corruption. We investigate this hypothesis by exploring the effect of disaster relief provided by the Federal Emergency

2008-01-01

319

The Tides--A Neglected Topic.  

ERIC Educational Resources Information Center

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)

Hartel, Hermann

2000-01-01

320

Sea anemone exposed at low tide  

NSDL National Science Digital Library

Sea anemones are sensitive to drying out. To avoid drying out during low tide and periods of intense sunlight, the anemones roll up to keep their tentacles moist. The outer body of the anemone is thick and tolerant of heat.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-05

321

Tides at the Battery, New York  

NSDL National Science Digital Library

In this exercise, students use online data, spreadsheets, and graphs to analyze tidal fluctuations at the Battery in New York. They will be asked to examine and compare the observed and predicted tides, and then make their own predictions.

Burrows, Charles

322

Red Tides in the Australasian Region,  

National Technical Information Service (NTIS)

Australian waters are not subject to 'red tide' phenomena as a regular occurrence. Episodic water discolorations have been caused by blue-green algae (Trichodesmium), diatoms (Thalassiosira), prymnesiophytes (Phaeocystis) and especially dinoflagellates (N...

G. M. Hallegraeff

1987-01-01

323

Differences Between Climate and Weather  

NSDL National Science Digital Library

This activity will provide students with first hand knowledge of local weather changes and how they relates to local climates. After this activity students will understand the general distinctions between weather and climate, that daily weather measurements are highly variable compared to long-term climate data, and appreciate the difficulty of identifying climate trends based on limited data. The instructor guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners.

324

Application of geostatistics to evaluate partial weather station networks  

Microsoft Academic Search

Climatic data are an essential input for the determination of crop water requirements. The density and location of weather stations are the important design variables for obtaining the required degree of accuracy of weather data. The planning of weather station networks should include economic considerations, and a mixture of full and partial weather stations could be a cost-effective alternative. A

Muhammad Ashraf; Jim C. Loftis; K. G. Hubbard

1997-01-01

325

PRACTICES FOR QUALITY IMPLEMENTATION OF THE TIDEE \\  

Microsoft Academic Search

This paper outlines practices that ensure quality in administering, interpreting, reporting, and maintaining the 'Design Team Readiness Assessment' developed by the Transferable Integrated Design Engineering Education (TIDEE) consortium in the Pacific Northwest. A copy of the instrument can be downloaded from www.cea.wsu.edu\\/tidee. The instrument assesses design process, teamwork, and design communication skills in three different contexts. Previous work has demonstrated

Denny Davis; Michael Trevisan; Larry McKenzie; Steven Beyerlein; Patricia Daniels; Teodora Rutar; Philip Thompson; Kenneth Gentili

326

The Interpolation of Earth-Tide Records  

Microsoft Academic Search

A method is presented whereby earth-fide gravity records can conveniently be interpolated. It is based on the theoretical rigid-earth gravity tide\\/\\/o(t) and its time deriva- tive. The possibility is envisaged that earth-tide gravity records for any station may be gen- erated in their entirety by this method for any station for which a pair of constants has been determined. .

I. M. Longman

1960-01-01

327

Red Tide Current Status Statewide Information  

NSDL National Science Digital Library

This summary report of current red tide conditions around Florida includes a map of sampling results and regional status reports. Reports are generally updated on Friday afternoon and additional information, if available, is provided on Tuesday afternoon. The web page also includes links to hotlines and reporting sites for red tide effects on marine animals and humans, shellfish information, volunteer opportunities, subscriptions, and related websites.

2009-11-30

328

Red Tide and Harmful Algal Blooms  

NSDL National Science Digital Library

This Project Oceanography pdf document contains information and activities related to red tide and harmful algal blooms (HABs). The activities and lesson plans are designed for elementary school, middle school, and may be adapted for high school students. Articles include: harmful algal blooms, Florida red tide, implications of harmful algal blooms, and student information about harmful algal blooms. Activities are introduced with background information and include: "Growing Algae" and "Algal Explosion." The document also features activity extension projects and a glossary of terms.

Oceanography, Project

329

Mapping hurricane rita inland storm tide  

USGS Publications Warehouse

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.

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

2009-01-01

330

Asymmetric tide in Lake Vallunden (Spitsbergen)  

NASA Astrophysics Data System (ADS)

We observed strongly asymmetric tide in a channel connecting the Van Mijen Fjord and Lake Vallunden in Spitsbergen. The channel is approximately 100 m long, 10 m wide, and 1-2 m deep. Asymmetric tide was also observed in the lake. The form of the semidiurnal tide is described by a combination of only three harmonics (M2, S2 and M4) with different amplitudes and phases. The flood dominant form of the surface elevation in the channel (unlike the ebb dominant tide in the fjord) is formed over a horizontal distance of 50 m over a shallow bottom at the entrance to the channel. The tide in shallow places becomes asymmetric due to nonlinear effects caused by the influence of the bottom and especially by choking of the tidal flow over a sill that is located between the fjord and channel. We think that such a small distance, over which the form of the tide changes, is caused by the small scale of the channel related to the fjord. We suggest a numerical model related to these measurements.

Marchenko, A. V.; Morozov, E. G.

2013-11-01

331

Global modelling of surface and internal tides  

NASA Astrophysics Data System (ADS)

Almost 250 years ago Laplace formulated a system of hydrodynamical equations that can describe the dynamics of ocean tides given astronomical forcing and global topography. But these equations lack dissipation that is required to cause the observed slowdown of Earth's rotation. During the last 100 years the importance of two dissipative processes has been recognised: energy loss to a turbulent bottom boundary layer in shallow seas and, more recently, energy conversion from surface to internal tides (i.e. internal waves at tidal frequency). And this internal tide is now thought to play an important role in setting the global oceanic circulation, and, therefore, climate on Earth. Here, a new global numerical model of ocean tides is described. Special emphasis is placed upon accounting for the energy loss to internal tides in a simplified but physically consistent way, which is achieved via explicit modelling of linear internal wave generation at specified tidal frequencies. The model resolution is sufficiently high to resolve a few low-mode internal tides which capture the majority of barotropic-to-baroclinic energy conversion. The advantages (and limitations) of this approach are examined, by comparison with the model results obtained with popular internal wave drag parametrization schemes. Although our purely dynamical model is less accurate than data-constrained models, it is more flexible and can be used to explore tidal regimes of the past and future and their climatological implications.

Lapin, Vladimir; Griffiths, Stephen

2014-05-01

332

Weather Science Hotlist  

NSDL National Science Digital Library

The Franklin Institute Online offers the metadata Web site Weather Science Hotlist. The page contains dozens of links organized into ten topics that include Online Exhibits, Weather Right Now, Background Information, Severe Weather, El Nino/ La Nina, Historical Weather, Career Connections, Activities, Atmosphere, and Weather Forecasting. A great source for anyone looking for online weather information.

2008-04-11

333

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

334

Weather Tamers  

NSDL National Science Digital Library

Problem-based learning experiences that extend at least two weeks provide an opportunity for students to investigate a real-world problem while learning science content and skills in an exciting way. Meteorology provides a wealth of problems students can investigate while learning specific science concepts and skills found frequently in middle level national and state curricula standards. The hands-on activity described in this article helps students learn about the science behind weather events by planning, constructing, and testing models of cities exposed to a series of simulated hurricanes and tornado conditions.

Sterling, Donna R.; Frazier, Wendy M.

2007-03-01

335

Mountain Weather  

NSDL National Science Digital Library

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

336

Weather Photography  

NSDL National Science Digital Library

Ph.D. student Harald Edens describes himself as a "photographer of lightning, clouds, atmospheric optical phenomena and astronomy". His Web site entitled Weather Photography proves this by providing a stunning collection of photographs and movies of atmospheric optics, lightning, clouds, and astronomy. The author describes how the photographs were taken, what equipment was used, and even discusses many of the phenomenon being observed such as mirages and halos. An added bonus of this very interesting site is that the author generously allows free personal use of the photographs.

2000-01-01

337

Weather Activities  

NSDL National Science Digital Library

This entertaining, interactive website is the perfect tool to educate users about the basics of weather forecasting and reporting. The two educational modules, created by EdHeads, each contain three levels and are designed for grades four through nine. While discovering how to predict a three-day forecast, students learn about warm and cold fronts, wind direction and speed, high and low pressure systems, isobars, and humidity. Teachers can find a helpful guide discussing how best to use the site as well as providing an overview of science standards, lesson plans, and pre- and post-tests for students.

338

Destructive Weather  

NSDL National Science Digital Library

What are the effects of different types of destructive weather? Learn All About Hurricanes Record on your chart 3 things that you learned. Watch a Hurricane Video These are the devastating Effects of Hurricanes Learn All About Tornadoes Record on your chart 3 things that you learned. Watch a Tornado Video These are the devastating Effects of tornadoes Learn All About Thunderstorms Record on your chart 3 things that you learned. These are the devastating Effects of thunderstorms Follow these important tips To keep safe. ...

Alizabethirwin

2010-11-03

339

Atmospheric Tides in the Ionosphere. I. Solar Tides in the F2 Region  

Microsoft Academic Search

A theory, based on solar tides, is advanced to explain the anomalous seasonal, diurnal and geographical variations of F2 region ionization. It is shown that the horizontal winds due to these tides must cause electrons to move along the lines of the earth's magnetic field. The resultant motion has a vertical component. Account is taken of polarization of the medium

D. F. Martyn

1947-01-01

340

The impact of tides on mixing and freshwater export in the Laptev Sea  

NASA Astrophysics Data System (ADS)

The vast and shallow Laptev Sea shelf is seasonally ice covered and receives large amounts of freshwater runoff from the Lena River. This shelf is an important export region for sea ice and freshwater to the Arctic basin, and features strong vertical and horizontal gradients which separate the saline basin waters from the fresh coastal waters. Processes promoting shear instabilities and diapycnal mixing are therefore of interest for physical and biogeochemical properties. The Laptev Sea shelf features considerable shear in under-ice currents largely dominated by the baroclinicity in semidiurnal tides. We present an investigation into semidiurnal tides based on year-round oceanographic moorings from different locations across the Laptev Sea shelf. Harmonic analysis of ADCP records shows a strong depth-dependence in the clockwise tidal currents that can be linked to stratification and further shows large spatial and seasonal variability of tides. Total current magnitudes are stronger on the outer than on the inner shelf, and tides overall explain >80% of the current's variance throughout the year. On the inner shelf, tides play a comparatively greater role under sea ice (40-70%) than during open water periods (20-50%) when wind-induced inertial motions dominate. The ADCP records are further complemented by two cross-shelf microstructure transects which show episodes of intense turbulent kinetic energy dissipation in the pycnocline following the alignment of the semidiurnally rotating shear-vector and the surface forcing, hence underlining the potential influence of tides on diapycnal mixing. Our results highlight the potential of tides to vertically transport freshwater, heat and nutrients, and provide some first order insights into how the physical environment of this shelf may change with changing sea ice conditions.

Janout, Markus; Lenn, Yueng-Djern

2013-04-01

341

Propagating tides in the mesosphere  

NASA Technical Reports Server (NTRS)

A preliminary search has begun for evidence of tides in the 1-hr average line-of-sight mesospheric velocity data from the Urbana radar in the period 1978 to 1982, inclusive. Observations are restricted to the southeasterly component of those velocities. Since observations are only available for a fraction of a day due to the absence of night-time ionization in the Urbana mesosphere, it was decided to adopt an unusual procedure in the search; namely, to perform a Fourier analysis in the vertical direction and look for rotation in phase of vectors representing spatial frequency components. Propagating tidal modes would then show as vectors with a net rotation corresponding to their downward phase velocity. Five year monthly averages of hourly mean horizontal velocities inferred from the Urbana data are given. Consistent diurnal variation is seen for a number of months. These data were analyzed for vertical spatial periods of 3, 4.5, 6, 9, 12, and 24 km. When plotted as a function of time of day, many of the phasors tended to show a net rotation. The sense of rotation of a spinning vector in the complex plane can be determined objectively by computing the signed area swept out by the vector in saving from point to point. This calculation, indicated downward motion in 8 out of 12 months for the 9-km component and in 11 out of 12 months for the 24-km component. A comparison of the magnitudes of the 6 modes showed that the primary component was the 24-km component, a result confirmed by the tidal models of Forbes.

Bowhill, S. A.; Merewether, K. O.

1986-01-01

342

Bifurcation Analysis of Brown Tide by Reaction Diffusion Equation Using Finite Element Method  

NASA Astrophysics Data System (ADS)

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 analysed the stability of two cases, i.e., hydranth regeneration in the marine hydroid Tubulariaand 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.

Kawahara, Mutsuto; Ding, Yan

1997-03-01

343

The Global S$_1$ Ocean Tide  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

344

Modeling tides and their influence on the circulation in Prince William Sound, Alaska  

NASA Astrophysics Data System (ADS)

In the process of developing a real-time data-assimilating coastal ocean forecasting system for Prince William Sound, Alaska, tidal signal was added to a three-domain nested model for the region. The model, which is configured from the Regional Ocean Modeling System (ROMS), has 40 levels in the vertical direction and horizontal resolutions of 10.6km, 3.6km and 1.2km for its three nested domains, respectively. In the present research, the ROMS tidal solution was validated using data from coastal tide gauges, satellite altimeters, high-frequency coastal radars, and Acoustic Doppler Current Profiler (ADCP) current surveys. The error of barotropic tides, as measured by the total root mean square discrepancy of eight major tidal constituents is 5.3cm, or 5.6% of the tidal sea surface height variability in the open ocean. Along the coastal region, the total discrepancy is 9.6cm, or 8.2% of the tidal sea surface height variability. Model tidal currents agree reasonably well with the observations. The influence of tides on the circulation was also investigated using numerical experiments. Besides tides, other types of forcing fields (heat flux, wind stress, evaporation minus precipitation, and freshwater discharge) were also included in the model. Our results indicate that tides play a significant role in shaping the mean circulation of the region. For the summer months, the tidal residual circulation tends to generate a cyclonic gyre in the central Sound. The net transport into the Sound through Hinchinbrook Entrance is reduced. Tides also increase the mixed layer depth in the Sound, especially during the winter months.

Wang, Xiaochun; Chao, Yi; Zhang, Hongchun; Farrara, John; Li, Zhijin; Jin, Xin; Park, Kyungeen; Colas, Francois; McWilliams, James C.; Paternostro, Chris; Shum, C. K.; Yi, Yuchan; Schoch, Carl; Olsson, Peter

2013-07-01

345

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)

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 (usually) inhibits the complete collapse of atmospheric pCO2 is the accelerating formation of thick cation-deficient soils that retard chemical weathering of the underlying bedrock. Nevertheless, equatorial climate seems to be relatively insensitive to pCO2 greenhouse forcing and thus with availability of some rejuvenating relief as in arc terranes or thick basaltic provinces, silicate weathering in this venue is not subject to a strong negative feedback, providing an avenue for sporadic ice ages. The safety valve that prevents excessive atmospheric pCO2 levels is the triggering of silicate weathering of continental areas and basaltic provinces in the temperate humid belt. Increase in Mg/Ca ratio of seawater over the Cenozoic may be due to weathering input from continental basaltic provinces.

Kent, D. V.; Muttoni, G.

2012-09-01

346

The Weather Dude  

NSDL National Science Digital Library

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

Walker, Nick.

2002-01-01

347

The IERS Special Bureau for Tides  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

348

The Icelandic Information System on Weather and Sea State related to Fishing VesselsCrews and Stability  

Microsoft Academic Search

The Icelandic Maritime Administration's (IMA) weather and sea state information system increases safety for seafarers and contributes to more efficient fishing. The system is based on both real-time measurements and forecasts. The IMA website (http:\\/\\/vs.en.sigling.is) provides updated information every hour about weather and sea state, weather and tides in harbours, and wave height inside and outside harbours, using data from

Gisli Viggosson; Jon Bernodusson

349

FINITE ELEMENT MODEL FOR TIDES AND CURRENTS WITH FIELD APPLICATIONS.  

USGS Publications Warehouse

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.

Walters, Roy, A.

1988-01-01

350

Non-Stationary Internal Tides Observed with Satellite Altimetry  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

351

Non-stationary internal tides observed with satellite altimetry  

NASA Astrophysics Data System (ADS)

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-1 tidal internal waves. With some exceptions the non-stationary variance does not exceed 0.25 cm2. 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.

Ray, R. D.; Zaron, E. D.

2011-09-01

352

A Model for Teaching the Dynamical Theory of Tides.  

ERIC Educational Resources Information Center

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)

Railsback, L. Bruce

1991-01-01

353

Cockpit Weather Information Needs.  

National Technical Information Service (NTIS)

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 weat...

C. H. Scanlon

1992-01-01

354

Forecasting the Weather.  

ERIC Educational Resources Information Center

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)

Bollinger, Richard

1984-01-01

355

External Resource: Mechanical Weathering  

NSDL National Science Digital Library

A student activity with teacher's sheet, to give the students an opportunity to realize that all rocks weather mechanically and each specific rock type has its own particular rate of weathering. Mechanical weathering is the process of breaking down bedroc

1900-01-01

356

National Weather Service  

MedlinePLUS

HOME FORECAST Local Graphical Aviation Marine Rivers and Lakes Hurricanes Severe Weather Fire Weather Sun/Moon Long ... LOADING... Menu ? ACTIVE ALERTS ? FORECAST MAPS ? RADAR ? RIVERS, LAKES, RAINFALL ? AIR QUALITY ? SATELLITE ? PAST WEATHER ? Local forecast ...

357

New Miscellaneous Results in Tides from Topex/Poseidon  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

358

Automatic Red Tide Detection using MODIS Satellite Images  

Microsoft Academic Search

Red tides pose a significant economic and environmental threat in the Gulf of Mexico. Detecting red tide is important for understanding this phenomenon. In this thesis, machine learning approaches based on Random Forests, Support Vector Machines and K-Nearest Neighbors have been evaluated for red tide detection from MODIS satellite images. Detection results using machine learning algorithms were compared to ship

Wijian Cheng

2009-01-01

359

Initial results from new Northern Cascadia tide gauge network  

Microsoft Academic Search

The Cascadia Slow Earthquake Temporary Tide Gauge (CASSETT) Network is a temporary network of 10 tide gauges deployed during the summer of 2010 in NW Washington along the Strait of Juan de Fuca, Puget Sound, and the Washington coast at historical but now unoccupied NOAA tide gauge sites. The purpose of this deployment is to densify the existing network of

P. Vincent; R. J. Weldon; D. Livelybrooks; D. A. Schmidt; S. Alba; T. Maciel; J. Bug; B. Croes

2010-01-01

360

Sensitivity of the tides of Mercury to its interior structure  

Microsoft Academic Search

An accurate tidal potential series for Mercury has been calculated based on VSOP ephemerides. Due to the 3:2 resonance of Mercury's rotation with its revolution around the Sun, the tides on Mercury can not be divided into the three classically known tidal frequency bands for the Earth, the diurnal, semi-diurnal and long period tides. Instead, the tides all have periods

T. van Hoolst; C. Jacobs

2003-01-01

361

Predicting Weather and Understanding Weather Systems  

NSDL National Science Digital Library

The assignment requires students to observe the weather map in the newspaper for four consecutive days. On the first day they are instructed to choose a location somewhere in the country. The will record the weather conditions there and observe any weather systems that exist elsewhere in the country. They then make predictions of how they expect weather in their location to change over the subsequent three days.

Grandy, Carla

362

Global Ocean Tides. Part X. The Fortnightly Lunar Tide (Mf) Atlas of Tidal Charts and Maps.  

National Technical Information Service (NTIS)

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 ...

E. W. Schwiderski

1982-01-01

363

NOAA New England Red Tide Information Center: More About Red Tides and Harmful Algal Blooms  

NSDL National Science Digital Library

This web page features links to information about NOAA-funded harmful algal bloom (HAB) research, HAB species, and HAB toxins and their impacts on humans, marine environments, and coastal economies. It also offers a brief description of Red Tide.

National Ocean Service (NOS); Noaa

364

Palmer Automatic Weather Station  

NSF Publications Database

Title : Palmer Automatic Weather Station Type : Antarctic EAM NSF Org: OD / OPP Date : December 06 ... Environmental Action Memorandum (Palmer Automatic Weather Station) To: Files (S.7 - Environment ...

365

Tide Pools and the Life Within Them  

NSDL National Science Digital Library

This winning entry in the museum's Young Naturalist Awards 2001 by Talia, a 13 year old student from California, examines tidal pools and the animals that live in them. Her narrative essay reports on her three week study of the marine life she found in Doheny State Beach's tide pools.

366

Parents Who Moved against the Tide.  

ERIC Educational Resources Information Center

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)

Perske, Robert

2003-01-01

367

Harmful Algal Blooms: Brown Tide Blooms  

NSDL National Science Digital Library

This University of Maryland SeaGrant web page discusses brown tide blooms, particularly those caused by Aureococcus anophagefferens and Aureoumbra lagunesis in Rhode Island and Texas, respectively. The page explores the economic and ecological effects in both regions and highlights various theories regarding their formation and recurrence.

Kane, Andrew; Jacobs, Dan; The Aquatic Pathobiology Center, University of Maryland; SeaGrant

368

Mass. Declares a Red Tide Disaster  

NSDL National Science Digital Library

This CBS news article provides very general information about the massive red tide outbreak in New England in 2005. The article states that the outbreak is costing the shellfish industry $3 million per week, forcing Massachusetts to declare a state of emergency. The article features related external links.

CBS; Associated Press

369

Red Tide Kills Fish, Fouls Gulf Coast  

NSDL National Science Digital Library

This CBS news article reports a toxic algae bloom that spread along the Texas Gulf coast in 2000, killing millions of fish and fouling beaches with their remains. The article explains how red tide affects fish and describes health threats to humans.

News, Cbs

370

Ocean energy-waves, currents, and tides  

Microsoft Academic Search

An overview is presented on the mechanical forms of ocean energy; i.e., waves, currents, and tides. Following an introductory section on wave mechanics, each of the three forms of ocean energy is considered under the headings of the resource, device types for energy extraction, and prognosis for practical implementation.

J. Miles; B. Shelpuk

1981-01-01

371

Tides of the Eastern Bering Sea Shelf  

Microsoft Academic Search

The acquisition of a substantial amount of pressure-gauge and current-meter data on the Bering Sea shelf has permitted a much more accurate description of the tides than has previ­ ously been possible. Cotidal charts are presented for the M 2 and, for the first time, the N 2' K t , and 0t constituents, and tidal current ellipse charts for

Carl A. Pearson; Harold O. Mofjeld; Richard B. Tripp

372

Tide effects removed from well tests  

Microsoft Academic Search

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;

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

1995-01-01

373

Earth Tides and Lense–Thirring Effect  

Microsoft Academic Search

The general relativistic Lense—Thirring effect can be measured by inspecting a suitable combination of the orbital residuals of the nodes of LAGEOS and LAGEOS II and the perigee of LAGEOS II. The solid and ocean Earth tides affect the recovery of the parameter by means of which the gravitomagnetic signal is accounted for in the combined residuals. Thus an extensive

Lorenzo Iorio

2001-01-01

374

Nonlinearity in Rock: Evidence From Earth Tides  

Microsoft Academic Search

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

Duncan Carr Agnew

1981-01-01

375

Earth tide forcing of glacier drainage  

Microsoft Academic Search

Fourier analysis reveals that winter electrical self potential (SP), water pressure (PW), and electrical conductivity (EC) time series collected beneath Haut Glacier d'Arolla, Switzerland, are forced by earth and atmospheric tides. Forcing is dominant during periods of expanding bedrock, consistent with glacier substrate deformation periodically driving water from the ice body into the bed. This may modify the strength of

Bernd Kulessa; Bryn Hubbard; Giles H. Brown; Julia Becker

2003-01-01

376

Nonlinearity in rock - Evidence from earth tides  

NASA Technical Reports Server (NTRS)

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.

Agnew, D. C.

1981-01-01

377

Semidiurnal solar tides in the mountain atmosphere  

SciTech Connect

Harmonic analysis of Doppler radar wind profiler data west of the Rocky Mountains has identified a coherent semidiurnal wind system above the wintertime boundary layer at multiple sites in the region. The unusual characteristics of this mountain wind system (its semidiurnal frequency, amplitude, phase, and direction of rotation) suggest that is is a semidiurnal solar tide. Such tides have not been previously documented in the mountain atmosphere or in the troposphere generally but, because semidiurnal signatures are well known in surface barometric traces, and large amplitude semidiurnal tides are known in the upper atmosphere, they are not unexpected. Our future research on this semidiurnal cordilleran wind system will focus on obtaining sufficient data to resolve further the vertical structure, seasonal variation, and spatial variations of the wind system. Of particular interest is the role of the Rocky Mountains and other cordilleras in modifying the global tides. It remains to be seen whether semidiurnal cordilleran circulations will be of sufficient magnitude to be observed across major arcuate-shaped east-west-oriented mountain massifs such as the Alps. There, wind systems may develop in response to pressure gradients (Frei and Davies, 1993) that form across the Alps due to differences in the amplitudes and phases of semidiurnal and diurnal pressure oscillations on the north and south sides of the mountain barrier.

Whiteman, C.D.; Bian, X.

1994-09-01

378

In Brief: Red tide Web site  

NASA Astrophysics Data System (ADS)

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.

Showstack, Randy; Kumar, Mohi

2008-06-01

379

Ocean Energy-Waves, Currents, and Tides.  

National Technical Information Service (NTIS)

An overview is presented on the mechanical forms of ocean energy; i.e., waves, currents, and tides. Following an introductory section on wave mechanics, each of the three forms of ocean energy is considered under the headings of the resource, device types...

J. Miles B. Shelpuk

1981-01-01

380

Arctic Ocean tides from GRACE satellite accelerations  

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

381

WeatherNet  

NSDL National Science Digital Library

WeatherNet, brought to us by The Weather Underground at University of Michigan, aims to be the premier site of weather links on the Internet. Besides the topical tropical storm page, you can view Accu-Weathers graphics including Nexrad imagery, satellite photos, surface maps, and forecast maps.

1998-01-01

382

Teaching Weather Concepts.  

ERIC Educational Resources Information Center

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…

Sebastian, Glenn R.

383

Backyard Weather Station  

NSDL National Science Digital Library

Students use their senses to describe what the weather is doing and predict what it might do next. After gaining a basic understanding of weather patterns, students act as state park engineers and design/build "backyard weather stations" to gather data to make actual weather forecasts.

Integrated Teaching And Learning Program

384

Future Weather Station  

NSDL National Science Digital Library

In this activity students build dioramas of futuristic weather stations to demonstrate their knowledge of weather forecasting. They will work in groups to research modern forecasting equipment and techniques, and then build a weather station that will do something we cannot do at present (such as stopping tornadoes). They will present their dioramas and then discuss the pros and cons of controlling the weather.

385

Weather in Your Life.  

ERIC Educational Resources Information Center

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…

Kannegieter, Sandy; Wirkler, Linda

386

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

SciTech Connect

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?

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

2006-03-30

387

Modelling tides and surface drift in the Arabian Gulf—application to the Gulf oil spill  

NASA Astrophysics Data System (ADS)

A tide and surge forecasting model capable of predicting conditions for up to 5 days ahead has been developed to provide environmental data on tides, currents and particle trajectories in the Arabian Gulf. A two-dimensional depth-integrated model on a 5' × 5' grid of the entire Gulf, driven by a 10 constituent tidal forcing at the mouth near the Strait of Hormuz and by meteorological forecasts from the United Kingdom Meteorological Office global numerical weather prediction model was used to provide hourly distributions of the depth-averaged tidal and wind-driven currents. Following the discharge of oil from Mina Al Ahmadi into the Gulf in January 1991 an oil spill model was interfaced to the tide and surge model, providing forecasts of the movement and spread of the oil slick. The oil spill model used a three-dimensional particle tracking algorithm to model the dispersion of the oil so that surface and sub-surface concentrations could be determined. The effects of surface evaporation and decay of the oil were included in the model.

Proctor, Roger; Flather, Roger A.; Elliott, Alan J.

1994-04-01

388

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

NASA Technical Reports Server (NTRS)

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.

Hung, Ching-Cheh

2007-01-01

389

On modeling migrating solar tides  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

390

PHOTOMETRIC VARIABILITY OF THE T2.5 BROWN DWARF SIMP J013656.5+093347: EVIDENCE FOR EVOLVING WEATHER PATTERNS  

SciTech Connect

We report the discovery of a photometric variability in the bright T2.5 brown dwarf (BD) SIMP J013656.57+093347.3. Continuous J-band photometry has been obtained for several hours on four different nights. The light curves show a periodic modulation with a period of {approx}2.4 hr, a peak-to-peak amplitude of {approx}50 mmag and significant night-to-night evolution. We suggest that the light curve modulation is due to the BD's rotation and that the longer term variations come from surface features evolution and/or differential rotation. We obtained complementary observations over a single night in the J and K {sub s} bands; the object displays correlated photometric variability in both bands, albeit with smaller K {sub s}-band amplitude. The ratio of the K {sub s} and J variability amplitudes puts strong constraints on the physical mechanisms at play. Based on theoretical models of BD atmospheres, our results suggest that the atmosphere of SIMP0136 is comprised of both grain-free and colder (by {approx}100 K) grain-bearing cloudy regions. This discovery, and its interpretation, provide a natural explanation of the so-called J-band brightening.

Artigau, Etienne [Gemini Observatory, Southern Operations Center, Association of Universities for Research in Astronomy, Inc., Casilla 603, La Serena (Chile); Bouchard, Sandie; Doyon, Rene [Departement de Physique and Observatoire du Mont Megantic, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, QC, H3C 3J7 (Canada); Lafreniere, David [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)], E-mail: eartigau@gemini.edu, E-mail: bouchard@astro.umontreal.ca, E-mail: doyon@astro.umontreal.ca, E-mail: lafreniere@astro.utoronto.ca

2009-08-20

391

Weather Modification A Theoretician's Viewpoint.  

NASA Astrophysics Data System (ADS)

Early progress in weather modification is attributed to a healthy interaction between theory and experiment. During the 1970s, a divergence of approaches took place. A "theoretical/experimental" approach, exemplified by the Cascade Project, focused on testing scientific hypotheses; an "observational/experimental" approach, exemplified by the Colorado River Basin Pilot Project, sought to enhance understanding of the seeding process through more detailed observations.The theoretical/experimental school soon came to focus almost exclusively on natural cloud processes, leaving the field of weather modification nearly devoid of a theoretical component. It is suggested that this theoretical component is necessary to revitalize the field of weather modification.Key questions are addressed. These include 1) identification of clouds that are amenable to seeding; 2) glaciogenic versus hygroscopic seeding; 3) optimizing critical seeding variables, such as seed particle concentration for glaciogenic seeding and seed particle size for hygroscopic seeding; and 4) seeding for hail suppression.

Young, Kenneth C.

1996-11-01

392

Australian Severe Weather  

NSDL National Science Digital Library

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

393

What's the Weather?  

NSDL National Science Digital Library

In this lesson, students use daily observations, videos, and activities to learn about meteorology and the changing nature of weather. They will also identify weather events that are commonly reported in the news and discuss how weather affects lives. They should understand that weather can change daily and weather patterns change over the seasons, and that it has characteristics that can be measured and predicted. Suggestions for an optional field trip are also provided.

2005-01-01

394

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

USGS Publications Warehouse

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.

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

1985-01-01

395

Untangling the roles of wind, run-off and tides in Prince William Sound  

NASA Astrophysics Data System (ADS)

Prince William Sound (PWS) oceanic circulation is driven by a combination of local wind, large run-off and strong tides. Using a regional oceanic model of the Gulf of Alaska, adequately resolving the mean circulation and mesoscale eddies, we configure a series of three nested domains. The inner domain zooms in on Prince William Sound with a 1-km horizontal grid resolution. We analyze a set of four experiments with different combinations of run-off, wind and tides to demonstrate the relative influence of these forcing on the central Sound mean circulation cell and its seasonal variability. The mean circulation in the central PWS region is generally characterized by a cyclonic cell. When forced only by the wind, the circulation is cyclonic in winter and fall and strongly anticyclonic in summer. The addition of freshwater run-off greatly enhances the eddy kinetic energy in PWS partly through near-surface baroclinic instabilities. This leads to a much more intermittent circulation in the central Sound, with the presence of intense small-scale turbulence and a disappearance of the summer wind-forced anticyclonic cell. The addition of tides reduces the turbulence intensity (relatively to the experiment with run-off only), particularly in the central Sound. The generation of turbulent motions by baroclinic processes is lowered by tidal mixing and by modification of the exchange at Hinchinbrook Entrance. Tides have an overall stabilizing effect on the central Sound circulation. Tidal rectification currents help maintain a mean cyclonic circulation throughout the year.

Colas, François; Wang, Xiaochun; Capet, Xavier; Chao, Yi; McWilliams, James C.

2013-07-01

396

Tide-influenced sedimentary environments and facies  

SciTech Connect

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.

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

1988-01-01

397

Arctic Ocean tides measured by satellite  

NASA Astrophysics Data System (ADS)

The Gravity Recovery and Climate Experiment (GRACE) measures Earth's gravity field by gauging the acceleration of two satellites that travel about 220 kilometers apart—slight differences in acceleration between the two satellites provide information about the distribution of mass below the satellites. To get an accurate picture of Earth's gravity field, it is necessary to know how tides are contributing to GRACE measurements. However, tidal corrections have usually been made using data from satellite altimeters that do not cover the Arctic. To get around this problem, Killett et al. developed a new method of analyzing GRACE data that enabled them to extract Arctic Ocean tides. They suggest that applying their method could help improve GRACE data processing. (Journal of Geophysical Research-Oceans, doi:10.1029/2011JC007111, 2011)

Balcerak, Ernie

2011-12-01

398

Application of database technology to red tide remote sensing  

NASA Astrophysics Data System (ADS)

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.

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

2003-05-01

399

New England Red Tide Outbreak 2005  

NSDL National Science Digital Library

This Woods Hole Oceanographic Institution website provides general information about the 2005 outbreak of toxic alga Alexandrium fundyense, a type of algae that causes red tide. This bloom outbreak is the worst in New England since 1972 and occurred off of the Gulf of Maine. The site also addresses possible causes for the bloom, why the bloom was so intense and widespread, and its economic cost. The web page features color diagrams of infected sites, pictures, and links to related sites.

2009-07-16

400

New England Red Tide Outbreak 2005  

NSDL National Science Digital Library

This Woods Hole Oceanographic Institution website provides general information about the 2005 outbreak of toxic alga Alexandrium fundyense, a type of algae that causes red tide. This bloom outbreak is the worst in New England since 1972 and occurred off of the Gulf of Maine. The site also addresses possible causes for the bloom, why the bloom was so intense and widespread, and its economic cost. The web page features color diagrams of infected sites, pictures, and links to related sites.

Institution, Woods H.

401

Earth tide gravity maps for western Europe  

Microsoft Academic Search

Tidal gravity profiles completed in western Europe by the authors (twenty stations) are complemented with some others from independent stations to provide the first tidal gravity maps of this region of the world exhibiting a quite smooth behaviour of the tidal parameters. sDiurnal waves appear nearly undisturbed and could furnish an upper limit for the solid tide phase lag. sSemi-diurnal

P. Melchior; J. T. Kuo; B. Ducarme

1976-01-01

402

Global charts of ocean tide loading effects  

NASA Astrophysics Data System (ADS)

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 M2, S2, N2, K2, K1, O1, P1, Q1, Mf, Mm, Ssa of Schwiderski's tidal model. These new charts have a resolution of 1° × 1° 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. We 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 our algorithm of Farrell's convolution.

Francis, O.; Mazzega, P.

1990-07-01

403

Modeling tides around Pine Island, Antarctic  

NASA Astrophysics Data System (ADS)

Tide is one of the least studied factors in ocean-sea ice coupled systems, which poses great challenges in our understanding of such coupled systems and great uncertainty in the hindcast and forecast of climate. In order to study the effects of tides in coupled ocean-sea ice systems, tidal signal is added to a coupled ocean-sea ice model around Pine Island, Antarctic. The oceanic component of the coupled model, which has a horizontal resolution of 1km and 70 levels in the vertical direction, is configured from the Massachusetts Institute of Technology General Circulation Model (MITgcm). The tidal boundary condition is from Circum-Antarctic Tide Simulation (CATS2008a). When sea surface height is solved explicitly, Flather boundary condition proved to be an effective way to add tidal signal in a regional ocean circulation model. Instead of solving sea surface height explicitly, MITgcm separates the pressure field into surface, hydrostatic, and non-hydrostatic parts, and solves the pressure field as a Poisson equation. Our preliminary results indicate that using the Poisson equation method poses unique challenges when applying tidal boundary condition to MITgcm. Suitable numerical schemes will be designed to add tidal signal to MITgcm. Tidal solution from MITgcm will be compared with that from CATS and available observations.

Wang, X.; Schodlok, M.; Menemenlis, D.

2012-12-01

404

Body Tides of a Realistic Earth  

NASA Astrophysics Data System (ADS)

A precise modelling of the Earth tides is necessary to correct the space gravimetry observations, from satellites such as GRACE and GOCE. It is also useful to correct ground measurements, and even more important for superconducting gravimeters, which have a 10 nGal precision. The Earth response (deformation and gravity) to tides or atmospheric load is generally computed assuming radial symmetry in stratified Earth models, at the hydrostatic equilibrium. Our study aims at providing a new Earth tide model, which accounts for the whole complexity of a more realistic Earth. Our model is based on a dynamically consistent equilibrium state which includes lateral variations in density and rheological parameters (shear and bulk moduli), and interface topographies. We use a finite element method and we solve numerically the gravito-elasticity equations. The deviation from the hydrostatic equilibrium has been taken into account as a first order perturbation. The equations are written in the Fourier domain, in order to allow degree one translational and rotational modes of the Earth. We investigate the impact on Earth tidal response of an equilibrium state different from hydrostatic and of the topography of the interfaces, for a simple model of lateral variation: a spherical anomaly in the mantle, which can represent plumes and superplumes. At the M2 frequency (semi-diurnal), we estimate the order of magnitude of the perturbation as a function of the radius and physical parameters of the anomaly.

Metivier, L.; Greff-Lefftz, M.; Diament, M.

2005-12-01

405

Diagnosing Interactions of the Diurnal Tide with the MLT Background Atmosphere Using Data from the TIDI and SABER Instruments  

NASA Astrophysics Data System (ADS)

In the upper mesosphere the diurnal tide reaches its maximum amplitude and exhibits variability on a seasonal and interannual time scale. This variability results from the combined effects of source variability and interactions with the background atmosphere. The interaction with the background atmosphere is sometimes idealized in models as an entirely dissipative Rayleigh friction. In this investigation we use satellite data to determine the actual residual terms needed to produce balance in the basic state equations of momentum and thermal energy. Estimates are made for both the migrating (westward propagating zonal wave number 1) tide and also non-migrating tides, although the method does not work for the stationary (zonal wave number 0) tide. Tidal perturbations are determined from two month composites of data from the TIDI and SABER satellite instruments. The residual terms are found to have large components acting in quadrature to the tidal perturbations that may indicate interactions with gravity waves. The time dependence of the residual terms allow us to assess the extent to which they may contribute to tidal variability. The climatology of tidal mean wind interaction is also quantified using two month estimates of the Elliasen-Palm flux made over the time span of the TIMED satellite mission, 2002 to the present.

Riggin, D. M.; Ortland, D. A.; Lieberman, R. S.

2010-12-01

406

The Moon, the Sun, and Tides. A Learning Experience for Coastal and Oceanic Awareness Studies, No. 214. [Project COAST].  

ERIC Educational Resources Information Center

This unit for students in grades 6-12 is designed to provide an introduction to the variables that cause tides. Included are teacher background materials, a possible three-day schedule, master sheets for transparencies, student activity materials, tests, and references to selected films and books. (RH)

Delaware Univ., Newark. Coll. of Education.

407

Interactive Weather Information Network  

NSDL National Science Digital Library

Offered by the National Oceanic and Atmospheric Administration (NOAA), the Interactive Weather Information Network (IWIN) is a collection of interactive weather maps and satellite images that is updated every five seconds. Visitors can see cloud cover animation loops, NEXRAD Radar images of precipitation, a map of all current weather fronts, and an interactive national map to see information about any particular state. Other information on the site includes a listing of any active weather warnings, a link for world weather data, and more, making this a must-see site for all those users interested in the most current weather happenings anywhere.

2002-01-01

408

Edheads: Weather Activities  

NSDL National Science Digital Library

This great interactive resource allows you multiple opportunities to explore weather related concepts. After clicking start, you will learn how to report and predict the weather at the underground W.H.E.D weather caves! Each activity has three different levels, and each level is harder than the one before it. This resource also includes a teacher's guide (with pre- and post- tests) and links to additional weather related resources. These include a weather glossary, a Fahrenheit to Celsius & Celsius to Fahrenheit converter, and a link that provides information about interesting people in the weather field.

2010-01-01

409

Pilot weather advisor  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

410

Weather and Precipitation  

NSDL National Science Digital Library

How are different types of weather common in our everyday life? How can we use what we know about weather to go about everyday activities? First, use the Weather Chart to write down what you learn from each website. Then, go to Weather Information Website #1 and click on "What's the Weather?" to dress the bear for the day. Make sure you write it down on your graphic organizer. Next, go to Weather Information Website #3 and explore at least 5(clouds, thunderstorms, winter storms, etc.) of ...

Jones, Ms.

2012-04-12

411

The Weather Man  

NSDL National Science Digital Library

This project is designed to let you be "The Weather Man" and control the weather through simulation, and hands on experience, followed by guided questioning and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. How does humility play a role in weather? How does more or less change weather? 2. What is water vapor? Where does it come from? 3. What happens when the weather drops below zero degrees? ...

Grasser, Mrs. E.

2012-09-27

412

Vertical Crustal Movements in Italy from Tide Gauge and Satellite Altimetry data  

NASA Astrophysics Data System (ADS)

Our goal is to determine vertical crustal movement rates from tide gauge and satellite altimetry measurements. Tide gauges measure sea level, but as they are fixed to the coast, they sense both sea surface height variations and vertical crustal movements. Satellite altimetric measurements determine sea surface height variations directly and can be used to separate the crustal signal from the sea surface height variations in tide gauge measurements. We apply the methodology to the Southern Italy, an area of broad scientific interest, due to its high seismic risk and its location as standpoint for a great bridge that should connect Sicily to the Italian mainland, but it can be exported to any parts of the world where tide gauge observations are available. Along the Italian coastline 26 tide gauge stations with 10-years of continuous data are available. We have explored the sea level data statistically, including a study of the space-time variation of rates, of the optimal way of calculating rates and of the correlation-coefficients between stations. The tidal sea level change rates have a relatively large variability, greatly ascribable to the short time interval of analysis (10 years), and are comprised between -5 and +9 mm/yr with an approximate uncertainty of 0.5 mm/yr. The satellite altimetric data pose a challenge to the joint analysis, due to very different time resolution (10 days versus hourly sampling of tide gauges), sparse spatial sampling of the Mediterranean due to track distances, and the difficulty in acquiring altimetric data in the vicinity of the coast. We have analyzed the satellites Topex/Poseidon and Jason1. The study of Envisat data is under way and it could provide more detailed data, since its track distance is sensibly shorter, even if time sampling interval is 35 days. We explore also the satellite altimetric data statistically, investigating the correlation matrices of the data and the time-space variation of the sea surface change rates. We move along the tracks, trying to approach the coast as near as possible. We construct time series with 10 day sampling interval at discrete locations with the criterion of covering the Mediterranean homogeneously. We calculate histograms as we go near the coast and we find that at a distance of about 45 km from the coast the number of points drastically is reduced leading to a time series with many interruptions. We also find that the sea surface change rates derived from the altimeter have an even greater variability compared to the tide gauges for the same years, showing that changes far from the coast are greater than near the coast. We discuss the problem of how to use the altimeter data in those cases in which the tracks are far from the tide gauges, as is the case for the satellite Topex/Poseidon and the tectonically interesting tide gauge stations of Sicily and Calabria. An adequate space-time interpolation of the satellite data produces maps of spatial variations of sea surface change that are used in the study of the differential sea level rates of tide gauges. We show that geologically consistent crustal uplift rates are found for the highly seismic area of eastern Sicily and Calabria.

Braitenberg, Carla; Lavinia, Tunini; Barbara, Grillo; Nagy, Ildiko'

2010-05-01

413

NONLINEAR TIDES IN CLOSE BINARY SYSTEMS  

SciTech Connect

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 growth rates that are a factor of Almost-Equal-To N faster than the standard three-wave parametric instability. These are local instabilities viewed through the lens of global analysis; the coherent global growth rate follows local rates in the regions where the shear is strongest. In solar-type stars, the dynamical tide is unstable to this collective version of the parametric instability for even sub-Jupiter companion masses with P {approx}< a month. (4) Independent of the parametric instability, the dynamical and equilibrium tides excite a wide range of stellar p-modes and g-modes by nonlinear inhomogeneous forcing; this coupling appears particularly efficient at draining energy out of the dynamical tide and may be more important than either wave breaking or parametric resonance at determining the nonlinear dissipation of the dynamical tide.

Weinberg, Nevin N. [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Arras, Phil [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Quataert, Eliot; Burkart, Josh, E-mail: nevin@mit.edu [Astronomy Department and Theoretical Astrophysics Center, 601 Campbell Hall, University of California, Berkeley, CA 94720 (United States)

2012-06-01

414

The Semidiurnal Westward s=1 Tide in the Stratosphere  

NASA Astrophysics Data System (ADS)

The semidiurnal westward propagating zonal wavenumber 1 tide (2, 1) is the dominant tide in the high- latitude wind field in the upper mesosphere during the late spring and summer. Observed peak wind speeds are ~ 30 m/s. Simulations agree with observations in showing a dominant (2, 1) tide in the upper mesosphere with about the correct amplitude at high polar latitudes. In model simulations the (2, 1) tide originates in a nonlinear interaction between the migrating semidiurnal tide (2, 2) and a stationary s=1 planetary wave. The interaction occurs in the stratosphere and mesosphere. However, stationary planetary waves are essentially absent from the summertime stratosphere and mesosphere so the occurrence of the predicted (2, 1) tide in the summer mesosphere originates via an interaction in the winter hemisphere. Observations and simulations in the mesosphere indicate a connection with the zero wind line in the zonally averaged zonal winds. The models (Angelas i Coll and Forbes, 2002, Aso, 2007) agree in showing that the (2,1) tide is confined to the upper mesosphere. We have analyzed results from the GEOS-5 assimilation model and find a significant stratospheric (2, 1) tide. We have also analyzed balloon data from the CNES VORCORE campaign in which a total of 27 balloons drifted in the Antarctic polar stratospheric vortex during the late summer and spring of 2005, and confirm the existence of the (2, 1) tide. This is the first observation of a (2, 1) tide in the stratosphere insofar as we are aware. The existence of this tide in the stratosphere is hard to understand in terms of energy propagation from the winter hemisphere guided by the zero wind line, since this would guide energy into the mesosphere rather than the stratosphere. We will present the height- latitude structure of the (2, 1) tide in the Antarctic spring and will show its correlation with the zero wind line and wave energy flux found from the GEOS-5 data assimilation model.

Mechoso, C. R.; Walterscheid, R. L.; Gelinas, L. J.; Schubert, G.

2008-12-01

415

Long-period perturbations in Starlette orbit and tide solution  

SciTech Connect

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.

Cheng, M.K.; Shum, C.K.; Eanes, R.J.; Schutz, B.E.; Tapley, B.D. (Univ. of Texas, Austin (United States))

1990-06-10

416

Numerical study of baroclinic tides in Luzon Strait  

Microsoft Academic Search

The spatial and temporal variations of baroclinic tides in the Luzon Strait (LS) are investigated using a three-dimensional\\u000a tide model driven by four principal constituents, O1, K1, M2 and S2, individually or together with seasonal mean summer or winter stratifications as the initial field. Barotropic tides propagate\\u000a predominantly westward from the Pacific Ocean, impinge on two prominent north-south running submarine

Sen Jan; Ren-Chieh Lien; Chi-Hua Ting

2008-01-01

417

Impacts of vertically propagating tides on the mean state of the ionosphere-thermosphere system  

NASA Astrophysics Data System (ADS)

The National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) is utilized to understand the role that upward propagating tides play in determining the zonal mean state of the ionosphere-thermosphere system. A sensitivity assessment of the TIE-GCM shows that TIE-GCM solutions greatly depend on the lower boundary conditions. We also establish the veracity of our TIE-GCM solutions within and above the dynamo region. To isolate the mean effects of tidal dissipation, differences between TIE-GCM simulations with and without lower boundary tidal forcing as specified by the Climatological Tidal Model of the Thermosphere are investigated. Dissipation of the DW1, (diurnal westward propagating tide with zonal wave number 1), diurnal eastward propagating tide with zonal wave number 3, and SW2 (semidiurnal tide with zonal wave number 2) explains most of ˜10-30 m s-1 seasonal and latitudinal variability in zonal winds within the dynamo region, with SW2 playing a greater role than ascribed in previous studies. Tidal dissipation at low latitudes causes a 9% decrease (30% increase) in [O] ([O2]) number densities near the F2 layer peak, leading to at least a 9% decrease in peak electron density (NmF2) throughout the year. F2 layer peak height (hmF2) differences of -4 to 2 km at low latitudes are explained by variations in the field-aligned plasma motion driven by meridional wind differences induced by tidal dissipation. Compositional effects are mainly driven by DW1 and SW2, which differs from previous interpretations of tidal-driven composition changes by DW1 "tidal mixing" exclusively. We suggest that tides may produce a net transport of constituents in the thermosphere similar to the way that, e.g., gravity waves can drive net transport of sodium in the mesosphere.

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

2014-03-01

418

Visit to an Ocean Planet - Timing the Tides  

NSDL National Science Digital Library

Tide tables, commonly seen in newspapers and on television in coastal areas, show that comparable local high and low tides occur almost one hour later from one day to the next. The motion of the Moon as it revolves around the Earth largely accounts for the time lag. Students participating in this activity will investigate this time lag by using the tide time diagram and instructions which are provided. They should be able to describe how and why the times of low and high tide change from one day to the next.

419

Precise comparisons of bottom-pressure and altimetric ocean tides  

NASA Astrophysics Data System (ADS)

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 core-nutation 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.

Ray, R. D.

2013-09-01

420

On Observing the Weather  

NSDL National Science Digital Library

In this article, Mount Washington Observatory meteorologist Tim Markle shares the ins and outs of his daily weather-observing routine and offers insights on making weather observations at home or at school.

Crane, Peter

2004-05-01

421

Weather and Stroke Risk  

MedlinePLUS Videos and Cool Tools

... the lower right-hand corner of the player. Weather and Stroke Risk HealthDay February 13, 2014 Related MedlinePlus Page Stroke Transcript Weather changes may significantly affect stroke risk, a new ...

422

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. ...

423

In Depth Winter Weather  

NSDL National Science Digital Library

Winter Weather is an In-Depth Special Report form the National Center for Atmospheric Research. It contains articles, images, activities, video clips, and interactive graphs to inform learners about meteorology and weather in the colder seasons.

2012-01-01

424

Multipurpose Weather Roundup Program.  

National Technical Information Service (NTIS)

Program RWR9 reads Surface Airways Observations (SAO's) from the local AFOS database and reformats them into plain language collectives for Hourly, State, and Regional Weather Roundups. Output is suitable for direct transmission on the state weather wire....

W. E. Sunkel

1983-01-01

425

Favorite Demonstration: Differential Weathering  

NSDL National Science Digital Library

In this inquiry-based demonstration, the consumption of a Baby Ruth candy bar is used to nurture students' interest in chemical and physical weathering. In addition, two other concepts can be illustrated: the difference between weathering and erosion and

Francek, Mark

2002-10-01

426

Weather in Antarctica  

NSDL National Science Digital Library

This homepage includes information about the weather in Antarctica and links to pages on the climate, wind chill, clouds, snow and ice, and pressure and storms of Antarctica. The current weather conditions updated automatically at various stations are also provided.

Hutchings, Thomas

1998-01-01

427

Stormfax Weather Services  

NSDL National Science Digital Library

This site offers links to a variety of weather information, including national, international and local weather maps and forecasts, satellite and radar imagery, and severe weather warnings. There are also links to diverse resources such as fire maps, glacier inventories, snow depths, storm surges and tropical storms. There are reports and advisories about El Nino and La Nina. The site also has a glossary of weather terms and conversion charts for temperature, wind speed and atmospheric pressure.

2002-06-10

428

Atmospheric tides in the low-latitude E and F regions and their responses to a sudden stratospheric warming event in January 2010  

NASA Astrophysics Data System (ADS)

extensive analysis of atmospheric tides in the low-latitude thermosphere and their responses to a major sudden stratospheric warming (SSW) event (18-23 January 2010) is presented. The analysis is based on observational data from the Arecibo dual-beam incoherent scatter radar. Important findings of the present study are as follows. (1) The diurnal tide with an evanescent phase structure dominates the F region meridional wind field. The diurnal tide has a peak amplitude of 45 m/s occurring at about 245 km, and it is very stable throughout the nine consecutive days' observation. Below 114 km, the vertical structures of the diurnal tide in the meridional and zonal components are consistent, which resemble the classical solar S1, 1 tidal mode. (2) The F region semidiurnal tide is much weaker and has larger day-to-day variability than the diurnal tide. In the E region, the semidiurnal amplitudes in the meridional and zonal components grow continuously in the altitude ranges from 106 to 121 km and from 100 to 115 km, respectively. The vertical wavelength of the zonal component is estimated to be 45 km above 100 km, which is close to the solar S2, 4 and S2, 5 tidal modes. (3) The semidiurnal and terdiurnal tides respond strongly to the SSW while the impact that the SSW has on the diurnal tide in the meridional wind is limited. During the SSW event, the amplitudes of the semidiurnal and terdiurnal tides are enhanced in the F region but reduced in the upper E region.

Gong, Yun; Zhou, Qihou; Zhang, Shaodong

2013-12-01

429

Weather Maps in Motion  

NSDL National Science Digital Library

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

Burrows, Charles

430

Aviation weather services  

NASA Technical Reports Server (NTRS)

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.

Sprinkle, C. H.

1983-01-01

431

Pinpointing the weather  

Microsoft Academic Search

Accurately predicting weather in regions like the west, which have a variety of climates in high mountain, coastal, and desert sites, can be tricky. Now the National Weather Service (NWS) is testing an experimental computer model that will help forecasters predict weather conditions with greater detail. The Eta-10 model allows forecasters in 24 western NWS offices to monitor the development

Elaine Friebele

1997-01-01

432

Hot Weather Tips  

MedlinePLUS

... A A + A You are here Home HOT Weather Tips Printer-friendly version We all suffer in hot weather. However, for elderly and disabled people and those ... conditions such as vascular disease or diabetes, the weather does not have to hit 100 degrees to ...

433

Predicting Seasonal Weather  

NSDL National Science Digital Library

This module is about a new method of predicting seasonal weather. The site describes the effects of El Nino on global weather and the accuracy of the new model. It includes links to classroom resources for a variety of weather-based units.

Dybas, Cheryl

2008-12-07

434

Convective Weather Avoidance with Uncertain Weather Forecasts  

NASA Technical Reports Server (NTRS)

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 are likely to avoid. The automated system periodically updates forecasts and reassesses rerouting decisions in order to account for changing weather predictions. The main objectives are to reroute flights to avoid convective weather regions and determine the resulting complexity due to rerouting. The eventual goal is to control and reduce complexity while rerouting flights during the 20 minute - 2 hour planning period. A three-hour simulation is conducted using 4800 flights in the national airspace. The study compares several metrics against a baseline scenario using the same traffic and weather but with rerouting disabled. The results show that rerouting can have a negative impact on congestion in some sectors, as expected. The rerouting system provides accurate measurements of the resulting complexity in the congested sectors. Furthermore, although rerouting is performed only in the 20-minute - 2-hour range, it results in a 30% reduction in encounters with nowcast weather polygons (100% being the ideal for perfectly predictable and accurate weather). In the simulations, rerouting was performed for the 20-minute - 2-hour flight time horizon, and for the en-route segment of air traffic. The implementation uses CWAM, a set of polygons that represent probabilities of pilot deviation around weather. The algorithms were implemented in a software-based air traffic simulation system. Initial results of the system's performance and effectiveness were encouraging. Simulation results showed that when flights were rerouted in the 20-minute - 2-hour flight time horizon of air traffic, there were fewer weather encounters in the first 20 minutes than for flights that were not rerouted. Some preliminary results were also obtained that showed that rerouting will also increase complexity. More simulations will be conducted in order to report conclusive results on the effects of rerouting on complexity. Thus, the use of the 20-minute - 2-hour flight time horizon weather avoidance teniques performed in the simulation is expected to provide benefits for short-term weather avoidan

Karahan, Sinan; Windhorst, Robert D.

2009-01-01

435

North Adriatic Tides: Observations, Variational Data Assimilation Modeling, and Linear Tide Dynamics.  

National Technical Information Service (NTIS)

Fifteen open-sea time-series observations of tidal velocities and tidal bottom pressures for more than six months duration provide a new database for North Adriatic tides. The observations show nearly reversing tidal currents at most locations and increas...

H. Perkins J. W. Book M. Wimbush

2009-01-01

436

WeatherHawk Weather Station Protocol  

NSDL National Science Digital Library

This resource provides instructions on how to log atmosphere data using a WeatherHawk weather station. A weather station is setup to measure and record atmospheric measurements at 15-minute intervals and can be transferred to the GLOBE program via email. Students can view data for their school that are continuous and show variations within a day. The data collected includes wind speed and direction and pressure thereby supporting a more complete study of meteorology using GLOBE. Students pursue a more extensive set of research investigations.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

437

What's SO COOL about Red Tide?  

NSDL National Science Digital Library

This Mote Marine Laboratory magazine article details a new study by Sarasota Operations Coastal Oceans Observation Lab (SO COOL) that is using technology to track harmful algal blooms (HABs). Autonomous underwater vehicles (AUVs) are equipped with temperature and salinity meters as well as a "Breve-buster," which is an instrument that collects water samples and determines levels of red-tide causing algae by shining a light through the sample and noting the light absorbing characteristics within the sample (indicative of these algae).

Donald, David

2009-07-03

438

Red Tide Strands South African Rock Lobsters  

NASA Technical Reports Server (NTRS)

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 satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

2002-01-01

439

Red Tide Strands South African Rock Lobsters  

NASA Technical Reports Server (NTRS)

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 satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

2002-01-01

440

Impact of Tropospherically-Generated Tides on the Mean State of the Ionosphere-Thermosphere System  

NASA Astrophysics Data System (ADS)

It is now widely recognized that vertically-propagating tides exert significant variability on the ionosphere-thermosphere (IT) system. In particular, the impact of tropospherically-generated non-migrating tides on longitudinal variability of the IT system has been a topic of intense research in recent years. However, relatively little is known about how dissipation of these upward propagating waves affects the zonal mean state of the IT system. Herein we report on numerical experiments performed with the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) that explore this topic using tidal lower boundary conditions near 30 km from the Global Scale Wave Model 2009 (GSWM-09) for average solar conditions during September and December. Differences between simulations with and without tidal forcing are analyzed to establish the aggregate effects of tidal dissipation on the zonal mean circulation and temperature structure, minor species concentrations, and ionospheric parameters. Numerical experiments are also performed with several different combinations of tides at the lower boundary to identify those components that most effectively alter the zonal mean structure of the IT.

Jones, M.; Forbes, J. M.; Hagan, M. E.; Maute, A. I.

2012-12-01

441

Fabulous Weather Day  

NSDL National Science Digital Library

Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. After studying weather for three months, we celebrate what we have learned and stretch our thinking further into the weather world around us! 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 their understanding of how the weather works and how it can affect their lives. Our unit focused on guiding students to formulate explanations about animals based on scientific evidence.

Marshall, Candice; Mogil, H. M.

2007-01-01

442

External Resource: Weathering and Erosion  

NSDL National Science Digital Library

This activity includes background information about weathering, as well as simple demonstrations/activities to model how weather conditions contribute to weathering and erosion. Topics include: chemical weathering, dunes, erosion, floods, glaciers, physi

1900-01-01

443

Terminal weather information management  

NASA Technical Reports Server (NTRS)

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