Moon Shadow Research Articles

Tolerance and Recovery of Kentucky Bluegrass Subjected to Seasonal Wear

Kentucky bluegrass (Poa pratensis L.) is frequently established on sports fields that receive wear during one or more seasons. Differences exist among Kentucky bluegrass cultivars for seasonal performance characteristics such as spring green‐up and summer stress tolerance. The objective of this study was to determine whether the wear tolerance and recovery of Kentucky bluegrass cultivars were dependent on season. Twenty‐two Kentucky bluegrass cultivars, representing nine genetically diverse Kentucky bluegrass types, were established in September 2002 in North Brunswick, NJ on a loam. The effects of simulated wear were evaluated during spring, summer, and fall in 2004 and 2005. Generally, Kentucky bluegrass was more tolerant of wear during spring than summer or fall and recovery was more rapid after spring wear. The performance of many cultivars depended on season of wear; however, ‘Julia’ consistently exhibited the greatest wear tolerance as well as recovery. Compact‐Midnight Type cultivars (‘Midnight’, ‘Midnight II’, and ‘Liberator’) had good wear tolerance during fall wear, however were slow to recover after fall wear. ‘Cabernet’, ‘Lakeshore’, ‘Moon Shadow’, ‘Limousine’, and ‘Jefferson’ exhibited more rapid recovery from fall wear during the next spring. ‘Langara’, ‘Bedazzled’, and ‘Touchdown’ had poor wear tolerance and recovery during all seasons. The season(s) of play should be considered when selecting Kentucky bluegrass cultivars for sports fields.

Measurement of the antiproton/proton ratio at TeV energies with the ARGO-YBJ detector

Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. Cosmic rays are hampered by the Moon, therefore a deficit of cosmic rays in its direction is expected (the so-called Moon shadow). The Earth–Moon system acts as a magnetic spectrometer. In fact, due to the geomagnetic field the center of the Moon shifts westward by an amount depending on the primary cosmic ray energy. Paths of primary antiprotons are therefore deflected in an opposite sense in their way to the Earth. This effect allows, in principle, the search of antiparticles in the opposite direction of the observed Moon shadow. The ARGO-YBJ experiment, in stable data taking since November 2007 with an energy threshold of a few 100s of GeV, is observing the Moon shadow with high statistical significance. Using about 1 year data, an upper limit of the p ¯ / p flux ratio in the few-TeV energy region is set to a few percent with a confidence level of 90%.

Simulation of the cosmic ray Moon shadow in the geomagnetic field

An accurate Monte Carlo simulation of the deficit of primary cosmic rays in the direction of the Moon has been developed to interpret the observations reported in the TeV energy region until now. Primary particles are propagated through the geomagnetic field in the Earth–Moon system. The algorithm is described and the contributions of the detector resolution and of the geomagnetic field are disentangled.

Moon shadow on high energy cosmic ray in data of a small extensive air shower array

Data from a small air shower array were used to examine the cosmic ray shadow of the Moon at energies more than 100 TeV. A simple technique has been used for the analysis of this data. In this technique the number of EAS events with arrival directions falling in error circles centered about the moving moon is compared to the mean number of events falling in error circles with centers randomly chosen in the sky. For any assumed angular radius of the error circle the deficit in EAS event count in the direction of moon which is a moon-related effect is interpreted as the shadow of the moon. A simple theoretical model has been developed to relate the mean number of EAS events, N sky , to the angular radius of the error circle and has been applied to the counts from the moon’s direction in order to extract the physical parameters of the shadow of the moon. The technique and the theoretical model has been used on 1.7 × 10 5 EAS events recorded by a small air shower array.

Solar eclipse effects of 22 July 2009 on Sporadic-E

Abstract. The total solar eclipse of 22 July 2009, was visible from some regions of China and the intense sporadic-E (Es) that broke out during the solar eclipse period over the eastern China provided a unique chance to study solar eclipse effects on the Es-layer. The ground based high-frequency (HF) vertical-incidence and oblique-incidence backscatter radio systems in Wuhan and an HF oblique receivers located in Suzhou were operated to detect the Es-layer. The vertical, oblique and backscatter ionograms of 22 and 23 July were recorded, processed and analyzed. The analyzing results show that the critical frequency of Es, the hop number and power of the rays transmitted from Wuhan to Suzhou as well as the Doppler frequency shift of the one-hop oblique-incidence waves reflected by the Es-layer all increased during the solar eclipse period. These variations are displayed in the paper and explained to be induced by the wind-field, which is produced by the powerful meridional air flows from the sunshine region to the moon's shadow.

MULTI-TeV GAMMA-RAY OBSERVATION FROM THE CRAB NEBULA USING THE TIBET-III AIR SHOWER ARRAY FINELY TUNED BY THE COSMIC RAY MOON'S SHADOW

The Tibet-III air shower array, consisting of 533 scintillation detectors, has been operating successfully at Yangbajing in Tibet, China since 1999. Using the dataset collected by this array from 1999 November through 2005 November, we obtained the energy spectrum of $\gamma$-rays from the Crab Nebula, expressed by a power law as $(dJ/dE) = (2.09\pm0.32)\times10^{-12} (E/{\rm 3 TeV})^{-2.96\pm0.14} {\rm cm}^{-2} {\rm s}^{-1} {\rm TeV}^{-1}$ in the energy range of 1.7 to 40 TeV. This result is consistent with other independent $\gamma$-ray observations by imaging air Cherenkov telescopes. In this paper, we carefully checked and tuned the performance of the Tibet-III array using data on the moon's shadow in comparison with a detailed Monte Carlo simulation. The shadow is shifted to the west of the moon's apparent position as an effect of the geomagnetic field, although the extent of this displacement depends on the primary energy positively charged cosmic rays. This finding enables us to estimate the systematic error in determining the primary energy from its shower size. This error is estimated to be less than $\pm$12% in our experiment. This energy scale estimation is the first attempt among cosmic-ray experiments at ground level. The systematic pointing error is also estimated to be smaller than $0\fdg011$. The deficit rate and position of the moon's shadow are shown to be very stable within a statistical error of $\pm$6% year by year. This guarantees the long-term stability of point-like source observation with the Tibet-III array. These systematic errors are adequately taken into account in our study of the Crab Nebula.

KM3NeT: Study of the angular acceptance for a high energy neutrino telescope in the Mediterranean Sea

Simulations for the study of the angular acceptance for a high energy neutrino telescope in the Mediterranean Sea are performed in the frame of the KM3NeT Design Study. In particular we have investigated how the PMT orientation can affect the performance of a km3 detector based on towers with a pair of Optical Modules equipped with 10 in. PMTs at each edge of the storey. Some preliminary results for three different PMT orientations are presented and the expected effect on the detection of point-sources and a diffuse flux of very energetic neutrinos is discussed. Moreover, a first attempt to study the response to atmospheric muons for different PMT orientations was also undertaken aiming both at the rejection of the atmospheric muons mis-reconstructed as up-going and the detection of the Moon shadow. However, due to the large detector volume, a huge statistics is needed to achieve an adequate live-time. For this reason we started a mass production of atmospheric muons at several detector depths.

Operation and performance of RPCs in the ARGO-YBJ experiment

The ARGO-YBJ array for EAS detection at high altitude (4300 m a.s.l.) is the largest RPC-based detector in operation at present (active area of 6700 m 2 out of a total instrumented surface of about 10 4 m 2 ). The constant monitoring of the main operational and environmental parameters is essential for both keeping the detector status under control and understanding the detector behaviour more deeply. Exploiting the information provided by the ARGO-YBJ Detector Control System, the present status of the detector is described and some correlations between the environmental and the operational parameters of the ARGO-YBJ RPCs are shown. This study was performed using the monitored data from the complete ARGO-YBJ array which has been in operation since October 2007. Preliminary results on the observations of the Moon shadow and of γ -ray point sources are also presented.

The total solar eclipse of March 2006: overview

Abstract. This paper provides the overview of an integrated, multi-disciplinary effort to study the effects of the 29 March 2006 total solar eclipse on the environment, with special focus on the atmosphere. The eclipse has been visible over the Eastern Mediterranean, and on this occasion several research and academic institutes organised co-ordinated experimental campaigns, at different distances from eclipse totality and at various environments in terms of air quality. Detailed results and findings are presented in a number of component scientific papers included in a Special Issue of Atmospheric Chemistry and Physics. The effects of the eclipse on meteorological parameters, though very clear, were shown to be controlled by local factors rather than the eclipse magnitudes, and the turbulence activity near surface was suppressed causing a decrease in the Planetary Boundary Layer. In addition to the above, the decrease in solar radiation has caused change to the photochemistry of the atmosphere, with night time chemistry dominating. The abrupt "switch off" of the sun, induced changes also in the ionosphere (140 up to 220 km) and the stratosphere. In the ionosphere, both photochemistry and dynamics resulted to changes in the reflection heights and the electron concentrations. Among the most important scientific findings from the experiments undertaken has been the experimental proof of eclipse induced thermal fluctuations in the ozone layer (Gravity Waves), due to the supersonic movement of the moon's shadow, for the first time with simultaneous measurements at three altitudes namely the troposphere, the stratosphere and the ionosphere. Within the challenging topics of the experiments has been the investigation of eclipse impacts on ecosystems (field crops and marine plankton). The rare event of a total solar eclipse provided the opportunity to evaluate 1 dimensional (1-D) and three dimensional (3-D) radiative transfer (in the atmosphere and underwater), mesoscale meteorological, regional air quality and photochemical box models, against measurements.

L3+C: status of the data analysis

The L3+C muon spectrometer is a delicate detector setup to record cosmic ray muons. Several results on atmospheric muon spectrum, Moon shadow and anti-proton/proton ratio, muon flare detection, etc, have been achieved. The study of some other physics topics, such as e.g. the search for exotic phenomena, the research on muon bundle events, are still going on. The status of the L3+C data analysis is presented.

Preliminary results of the Moon shadow using ARGO-YBJ detector

ARGO-YBJ is a “full coverage” air shower detector consisting of Resistive Plate Chambers(RPCs) at the Yangbajing High Altitude Cosmic Ray Laboratory (Tibet, China) at 4300 m a.s.l. (lat=30.11° N, long=90.53° E). Using the data collected with a carpet of RPCs (1900 m 2 , about 1/3 of the whole ARGO-YBJ detector), the cosmic ray shadowing effect due to the Moon was studied. The 50% angular resolution is found to be ∼1.2° with the Chess-board method and the Moon shadow with a significance of 4.9 σ is found displaced by 0.7° westward and 0.5° northward with respect to the expected position by the equi-zenith angle Method.

Evidence of gravity waves into the atmosphere during the March 2006 total solar eclipse

Abstract. This study aims at providing experimental evidence, to support the hypothesis according to which the movement of the moon's shadow sweeping the ozone layer at supersonic speed, during a solar eclipse, creates gravity waves in the atmosphere. An experiment was conducted to study eclipse induced thermal fluctuations in the ozone layer (via measurements of total ozone column, ozone photolysis rates and UV irradiance), the ionosphere (Ionosonde Total Electron Content – ITEC, peak electron density height – hmF2), and the troposphere (temperature, relative humidity), before, during and after the total solar eclipse of 29 March 2006. We found the existence of eclipse induced dominant oscillations in the parameters related to the ozone layer and the ionosphere, with periods ranging between 30–40 min. Cross-spectrum analyses resulted to statistically significant square coherences between the observed oscillations, strengthening thermal stratospheric ozone forcing as the main mechanism for GWs. Additional support for a source below the ionosphere was provided by the amplitude of the oscillations in the ionospheric electron density, which increased upwards from 160 to 220 km height. Even though similar oscillations were shown in surface temperature and relative humidity data, no clear evidence for tropospheric influence could be derived from this study, due to the modest amplitude of these waves and the manifold rationale inside the boundary layer.

Moon shadow by cosmic rays under the influence of geomagnetic field and search for antiprotons at multi-TeV energies

We have observed the shadowing of galactic cosmic ray flux in the direction of the moon, the so-called moon shadow, using the Tibet-III air shower array operating at Yangbajing (4300 m a.s.l.) in Tibet since 1999. Almost all cosmic rays are positively charged; for that reason, they are bent by the geomagnetic field, thereby shifting the moon shadow westward. The cosmic rays will also produce an additional shadow in the eastward direction of the moon if cosmic rays contain negatively charged particles, such as antiprotons, with some fraction. We selected 1.5 × 10 10 air shower events with energy beyond about 3 TeV from the dataset observed by the Tibet-III air shower array and detected the moon shadow at ∼40 σ level. The center of the moon was detected in the direction away from the apparent center of the moon by 0.23° to the west. Based on these data and a full Monte Carlo simulation, we searched for the existence of the shadow produced by antiprotons at the multi-TeV energy region. No evidence of the existence of antiprotons was found in this energy region. We obtained the 90% confidence level upper limit of the flux ratio of antiprotons to protons as 7% at multi-TeV energies.

RESULTS FROM L3+C

The L3+C measurement of the momentum spectrum of atmospheric muons between 20 and 3000 GeV for zenith angles ranging from 0° to 58° is presented and compared to theoretical predictions. An upper flux limit on the antiproton to proton ratio using the moon shadow is reported and an overview on the ongoing L3+C data analysis is given.

Atmospheric Surface-Layer Processes During the Total Solar Eclipse Of 11 August 1999

The central path of the total solar eclipse (TSE) of 11 August 1999 mostly passedthrough a region of active monsoon in India, with the eclipse ending around localsunset. Measurements in the surface layer (SL) were carried out close to the eclipseaxis at Akola (20°42' N, 77°2' E) in central India. The globalradiation flux reaching the surface vanishes around totality at 1803:24 (LT), followedby a small recovery before again dipping to zero at sunset. The temperatures in the SL, and subsoil at 50-mm depth, show a local minimum with a lag of about 10 min after the second contact, whereas the lag appears to vanish when the temperature series is detrended. The SL exhibits near-neutral, though generally stable, conditions from about 1500 hr itself due to heavy cloud cover followed by the eclipse-induced cooling of the surface. The wind component across the eclipse axis vanishes at totality, the wind vector aligning with the azimuth of the traversing moon shadow. The deceleration of the mean flow can be due to the combined effect of the colder surface and downward heat flux, where the locally altered horizontal temperature gradients may cause, as in this instance, the cessation of the cross flow. The oscillations in temperature and wind that show significant peaks, around 90–100 min as well as the semi-period of the eclipse near 60 min, persist for several hours past the eclipse event. A fresh analysis of the published data on the TSE of 7 March 1970 shows spectral peaks in the temperature nearly coincident with those already reported from the surface pressure records. The oscillations in the SL fields during the two TSE events are very similar implying that the source mechanism is also likely to be the same in both the cases.

The Phoenix Award of the Children's Literature Association: 1995-1999 (review)

Reviewed by: The Phoenix Award of the Children's Literature Association: 1995-1999 Ruth Anne Thompson (bio) The Phoenix Award of the Children's Literature Association: 1995-1999. Edited by Alethea Helbig and Agnes Perkins. Latham, MD: Scarecrow, 2001 The pleasures of this volume are those of a good dinner party: old friends and new, good conversation, a variety of perspectives and interesting things to talk about. First, however, some context is needed. The Phoenix Award is given to the author (or the estate of an author) of a children's book of high literary quality that was published in English twenty years earlier that did not win a major award at the time of its original publication. Two previous volumes in this series have already appeared, the first covering the awards from 1985 through 1989, and the second, from 1990 through 1994. Every year at the Children's Literature Conference, the Phoenix award committee presents the choices of both the award winner and any honorable mentions books. The task is daunting, the possibilities are extensive, and the final decision, as with any such award, is sometimes contentious. But this volume of papers, edited for publication, does credit to the work of the editors and their committees and enables readers to revisit old favorites and to discover new ones. In addition, the book contains brief summaries of each work, a biography of the author, and a list of his/her other works. This makes the volume a fine reference tool, but it is also more than that. There are transcripts of the authors' acceptance speeches, usually delivered at the annual conference banquet in person or by a representative. The opportunity to hear about the genesis of each work and to see into the mind and feelings of its author is a particularly strong and effective aspect of this book. The essays about other works by the award-winning authors are useful in extending the context and characteristics of each author and offer a wider perspective than the single celebratory analysis. This volume covers the awards to Laurence Yep's Dragonwings (1995 winner), Alan Garner's The Stone Book (1996), Robert Cormier's I Am the Cheese (1997), Jill Paton Walsh's A Chance Child (1998), and E. L. Konigsburg's Throwing Shadows (1999). The honor books also receive critical treatment: Tuck Everlasting by Natalie Babbitt (1995), Abel's Island by William Steig (1996), Beauty by Robin McKinley (1998), and The Devil in Vienna by Doris Orgel (1998), and The Disappearance by Rosa Guy (1999) and Words by Heart by Ouida Sebestyen (1999). The themes that appear in these works—multiculturalism, child abuse, immortality, myth—have a relevance that echoes as clearly now as when they first appeared, validating the appropriateness of their selection. As significant as the themes is the quality of literary craftsmanship that distinguishes them. Adrienne Kertzer's perceptive essay focuses on the nature of translation in Yep's Dragonwings. Her analysis of the story of Chinese immigrants in California at the turn of the century revolves around the ways in which communication moves beyond the particularities of language. The struggle of Moon Shadow to adapt to the alien American culture parallels the struggle to find equivalents for words and concepts that cannot be literally translated. The [End Page 215] universal desire for flight dominates Moon Shadow's father as he dreams of his former life as a dragon. But he must learn that science and machinery are not the solution to escape to a greater and purer realm. In another essay that examines the way in which language functions, Lisa Rowe Fraustino's discussion of the bleak vision of Cormier's I Am the Cheese explores the ways that lying is a protection for Adam in his intense isolation and self doubt. Particularly valuable is her summary of critical and reader responses to the novel. Reading this in light of Cormier's statement of intent in writing the book gives the reader a solid base on which to rest a response to the problematic theme and ending. In Garner's The Stone Book, Linnea Hendrickson sees the celebration of craftsmanship and the synthesis of the dichotomies of...

Observation of γ-sources using a new reconstruction technique in the CLUE experiment

The CLUE experiment, located in La Palma island at 2200 m a.s.l., is an array of 3×3 telescope, detecting the UV (190 – 230 nm) Čerenkov light produced by atmospheric showers. Since atmospheric absorption in the UV range is higher than in the visible range, CLUE cannot apply existing algorithms normally used in IACT experiments to determine primary cosmic ray direction. In this paper we present a new method developed by CLUE. The algorithm performances were evaluated using simulated showers. Using the new technique, preliminary results of last two years observational campaigns on the Crab Nebula and on Markarian 421 are presented, showing a clear signal on both sources. The CLUE experiment collected also data with the telescopes aiming directly at the Moon: we expect improvements also on the Moon Shadow measurement adopting the new method.

Changes in surface UV solar irradiance and ozone over the balkans during the eclipse of August 11, 1999

Intensive measurements of UV solar irradiance, total ozone and surface ozone were carried out during the solar eclipse of 11 August 1999 at Thessaloniki, Greece and Stara Zagora, Bulgaria, located very close to the footprint of the moon's shadow during the solar eclipse with the maximum coverage of the solar disk reaching about 90% and 96% respectively. It is shown that during the eclipse the diffuse component is reduced less compared to the decline of the direct solar irradiance at the shorter wavelengths. A 20-minute oscillation of erythemal UV-B solar irradiance was observed before and after the time of the eclipse maximum under clear skies, indicating a possible 20-minute fluctuation in total ozone presumably caused by the eclipse induced gravity waves. The surface ozone measurements at Thessaloniki display a decrease of around 10–15 ppbv during the solar eclipse. Similarly, ozone profile measurements with a lidar system indicate a decrease of ozone up to 2 km during the solar eclipse. The eclipse offered the opportunity to test our understanding of tropospheric ozone chemistry. The use of a chemical box model suggested that photochemistry can account for a significant portion of the observed surface ozone decrease.

The effect of the 1999 total solar eclipse on the ionosphere

The localised “night” created as the moon's shadow travelled across the Earth during the total solar eclipse of 11th August 1999, produced changes in the ionosphere across Europe that were monitored with a variety of modern instrumentation. The passage of the 100km wide, super-sonic lunar shadow offered the opportunity to examine the changes in electron densities, radio absorption, neutral wind patterns and the possible generation of waves in the layers of the ionosphere. All these for an event for which the cause of the disturbance can be calculated with accuracy. Reported here are the results from the vertical ionosondes located under the path of totality and in the partial eclipse region and dual frequency GPS TEC measurements. The ionosondes showed that even in the partial shadow the peak electron densities of the F & E ionospheric layers decreased by as much as 20–35%. The TEC measurements showed that the vertical equivalent line integrated electron density dropped by 15% at the 97% partial eclipse north of the path of totality. The consequences of these observations are discussed in relation to making model predictions.

The influence of the 11 August 1999 total solar eclipse on the weather over central Europe

Using a hydrostatic regional weather prediction model, the tropospheric response to the total solar eclipse on the 11 August 1999 is simulated over central Europe both with real time data and for a water vapor and cloud free scenario. The solar constant in the model is reduced stepwise along the surface path of the moon's shadow, reaching a value of 0 W/m 2 for a typical time span of 2 minutes during totality. In the presence of a large scale upper tropospheric trough centered over western Europe, the predicted radiative cooling ranging from -2°C over the UK, France and Germany to -5°C along the almost cloudless coast line of Croatia is in good agreement with observations. Over southeastern Europe the maximum cooling reaches -6°C to -7°C and the maximum sea surface pressure rise is enhanced from +0.4 hPa to +1.2 hPa, when the simulation is done without water vapor and clouds. The normally observed wind reduction is simulated as well as the temperature dependent increase of relative humidity near the ground. For some minutes even a slight cyclonic circulation is shown by the model surface winds. The upper air response to the eclipse is clearly correlated with the distribution of water vapor and clouds. The temperature and geopotential signals at the 500 hPa level are in the order of -0.01°C and -1 gpm remaining well below the sensitivity of routine sensors.