京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19168号 / 理博第4108号 / 新制||理||1591(附属図書館) / 32160 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 重 尚一, 准教授 林 泰一, 教授 余田 成男 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Spatial and temporal variation in foliar gas exchange on both a diurnal and seasonal scale was examined in 15-year-old fertilized and non-fertilized loblolly pine in the upper and lower thirds of crowns in stands located in the North Carolina sandhills. Photosynthesis rates between control and fertilized stands for both seasonal and diurnal measurement periods were different during only three months. Photosynthesis rates were consistently greater in the upper third of the crown compared to the lower third. Seasonal trends in both conductance and transpiration closely resembled trends found in seasonal photosynthesis. Foliar nitrogen concentrations were greater in fertilized stands for all months sampled. However, nitrogen content generally did not correlate with photosynthesis rates. Mean monthly water use efficiencies were significantly higher in fertilized stands during two months and were usually greater in upper crown foliage. Common empirical gas exchange models reveal that light and vapor pressure deficit (VPD) explain a majority of the variation observed in photosynthesis and transpiration, respectively. Conductance was not modeled since environmental variation did not adequately explain conductance patterns. Predicted light response curves reveal that upper crown foliage has higher maximum photosynthesis rates, respiration rates, light compensation points, and lower initial quantum yield compared to lower crown foliage. Models predict that foliage from fertilized stands is more sensitive to VPD and light during the growing season. Transpiration models predict highly variable responses to VPD depending on the treatment combination and season. Model R-square and predicted gas exchange values suggest that seasonal acclimation occurred. / Master of Science

Contexte et objectif – Les patients âgés gonarthrosiques présentent une dégradation du contrôle postural. Les méthodes non pharmacologiques sont aujourdhui recommandées comme option de première intention dans la gestion de l’arthrose. L’hydrothérapie fait partie des moyens de rééducation à disposition des patients âgés atteints d’arthrose du genou pour ses effets antalgiques et musculaires. Cependant, peu d’études sont actuellement disponibles concernant l’effet de l’hydrothérapie sur le contrôle postural, associée ou non à des programmes de rééducation individuels ciblés. Par ailleurs, le contrôle postural est susceptible de variations diurnes. Cette étude a eu pour objet de décrire le contrôle postural des personnes gonarthrosiques à quatre périodes de la journée, puis de comparer l’amélioration du contrôle postural au cours de deux programmes de rééducation différents recourant à l’hydrothérapie. Matériel et méthodes - Deux-cent-quatre-vingt quatre patients souffrant d’arthrose du genou ont été inclus dans cette étude. Le bilan posturographique a été réalisé une semaine avant la cure thermale en condition simple (yeux ouverts, support stable) et en conditions sensorielles contradictoires (vision faussée ou indisponible, proprioception perturbée). Pour évaluer les variations diurnes de la stabilité posturale, les patients ont été randomisés à quatre périodes d’essai dans la journée définies comme suit : 8h-10h, 10h-12h, 13h-15h, 15h-17h. L’influence du sexe, de l’âge, de la taille, du poids et de l’indice de masse corporelle sur la stabilité posturale a été évaluée. La gonalgie a également été évaluée à quatre périodes d’essai. Par la suite, les patients ont été randomisés en deux groupes de rééducation différents pour recevoir des traitements aquatiques : groupe cure classique (hydrothérapie efficace prouvée, c’est-à-dire groupe témoin) et groupe cure active (hydrothérapie combinant des programmes de réhabilitation individuels ciblés). Les bilans de posturographie statique ont été réalisés respectivement à 21 jours, 42 jours et 90 jours après le début de l’hydrothérapie. Résultats –Les tests posturographiques ont été réalisés chez 241 patients (âge moyen : 64,8 + 8,7 ans ; 82 hommes). Le contrôle de l’équilibre était plus efficace l’après-midi que le matin à la fois dans les conditions simple (p = 0,012) et sensorielle contradictoire (p = 0,047), en particulier en début d’après-midi lorsque la vision et la proprioception étaient disponibles (p = 0,026) ou perturbées (p = 0,019). La gonalgie a été plus prononcée le matin que l’après-midi (p < 0,001). La variation diurne du contrôle postural était plus marquée chez les patients plus âgés, de poids plus élevé, de sexe masculin, dans les conditions d’essais différentes (p < 0,05). Les deux cures d’hydrothérapie ont eu des effets curatifs considérables sur la restauration du contrôle de l’équilibre. Une meilleure précision des oscillations posturales a été constatée dans le groupe cure active par rapport au groupe cure classique, 42 jours après le début de l’hydrothérapie (p = 0,020), en particulier lorsque la proprioception a été perturbée avec (p = 0,028) ou sans (p = 0,025) vision disponible. Dans les deux groupes a été observée une stabilité posturale comparable dans un délai de trois mois. Conclusions - Cette étude a montré une meilleure stabilité posturale chez les patients atteints d’arthrose du genou, en début d’après-midi par rapport à la fin de matinée dans les situations sensorielles simples ou contradictoires. Il a été constaté que ces variations étaient également liées à l’âge, au sexe, au poids et pourraient être expliquées par la douleur articulaire fluctuante dans la journée. Considérée comme un traitement non pharmacologique applicable et recommandé, l’hydrothérapie est bénéfique à l’amélioration de la stabilité posturale chez les patients âgés atteints d’arthrose du genou, en particulier combinant un programme de réhabilitation individuel ciblé. [...] / Background and Objective – Increasing evidence supports balance control impairment in elderly patients with knee osteoarthritis (OA). Current guidelines recommend non-pharmacologic methods as first-line options in the management of OA. Hydrotherapy is a beneficial training medium for rehabilitation in elderly knee OA patients. However, few indications at present are available concerning the effect of hydrotherapy combining with targeted individual rehabilitation programs to improve balance control. Meanwhile, there is limited data on diurnal variation of balance control in these patients. This study aimed to investigate postural stability in elderly patients with symptomatic knee OA during different periods in a daytime before the spa therapy, then to study the results obtained before and after hydrotherapy to compare the improvement of balance control in these patients in two different water-based rehabilitation programs. Materials and Methods – Two-hundred and eighty-four knee OA patients were enrolled in this study. Static posturography using a vertical force platform was performed one week before spa therapy in simple (eyes open, firm support) and conflicting sensory (vision altered or unavailable, proprioception altered) conditions. To assess diurnal postural variations, patients were randomized to four testing sessions in a daytime defined as follows: 8-10am, 10-12am, 1pm-3pm, 3pm-5pm. Influence of sex, age, height, weight, and body mass index on postural stability was evaluated. Knee pain was also assessed in four testing sessions. Patients were then randomized to two different rehabilitated groups to receive spa therapies. Classic treatment group as a control received the efficacy proven spa water therapy, and active treatment group received spa water therapy combining with targeted individual rehabilitation programs. Static posturographies were carried out respectively in 21 days, 42 days and 90 days after the beginning of hydrotherapy. Results – Posturographic tests were completed for 241 patients (mean age: 64.8 + 8.7 years; 82 males). Balance control was more efficient in the afternoon than in the morning both in simple (p = 0.012) and conflicting sensory conditions (p = 0.047), especially in early afternoon when vision and proprioception were available (p = 0.026) or disturbed (p = 0.019). Patients’ knee pain was more pronounced in the morning than in the afternoon (p < 0.001). Diurnal variation of balance control was more noticeable in older, heavier, and male patients under different testing conditions (p < 0.05). Both the water-based therapies had considerable curative effect on balance control restoration. Better postural sway precision were found in active group than classic group 42 days after the beginning of hydrotherapy (p = .020), especially when proprioception was interfered with (p = .028) or without (p = .025) an available vision. Both of the groups have been observed a comparable postural stability in a three-month term. Conclusions – This study showed that better postural stability was observed in patients with knee OA in early afternoon than in late morning in simple and conflicting sensory situations. These variations appeared also to be related to age, sex, and weight and could be explained by fluctuant joint pain in a daytime. As feasible and recommended non-pharmacologic treatment, hydrotherapy is beneficial to the improvement of postural stability in elderly patients with knee OA, especially combining with targeted individual rehabilitation programs. These findings are important for future studies aiming at enhancing postural stability in knee OA patients and should be taken into account in the management of knee OA to generate applicative approaches to prevent the occurrence of adverse events in patient’s daily life.

In recent years, the rapid development of economy and industry in Xiamen Bay causes serious environmental problems, particularly poor air quality and visibility impairment. There are no large-scale industrial emission sources in Kinmen Island, however, its ambient air quality is always the poorest in Taiwan. Moreover, ambient air quality monitoring data showed that PM10 concentrations varied in daytime and at nighttime. Consequently, this study tired to ascertain the potential causes for this phenomenon. This study selected ten particulate matter (PM) sampling sites at Xiamen Bay, including five sites at Kinmen Island and five sites at metro Xiamen. Particulate matter sampling was conducted in daytime (8:00-17:00) and at nighttime (17:00-8:00), which included regular and intensive sampling. Regular sampling was conducted to collect PM10 with high-volume samplers three times a month from April 2009 to April 2010, while intensive sampling was conducted to collect fine (PM2.5) and coarse (PM2.5-10) particles with dichotomous samplers and particle size distribution with a MOUDI at site B2 for consecutive 5 days in the spring and winter of 2009~2010. After sampling, the physicochemical properties of PM, including mass concentrations, particle size distribution, water- soluble ionic species, metallic elements, and carbonaceous contents were further analyzed. The level of atmospheric PM is affected by meteorological condition, thus PM10 concentrations in winter and fall was much higher than those in spring and summer. Results from backward trajectories showed that the concentrations of PM10 blown from the north were generally higher than those from the south. Furthermore, t-test analysis indicated that PM10 concentrations in daytime and at nighttime at site B3 were significantly different (p-value<0.05). During the intensive sampling periods, PM10 concentrations were mainly affected by coarse particles compared to fine particles. The highest concentration for fine and coarse particle modes occurred at the size ranges of 0.32~0.56 £gm and 3.2~5.6 £gm, respectively. The most abundant water-soluble ionic species of PM10 were secondary inorganic aerosols (SO42-, NO3-, and NH4+) which accounted for 85% of total ions. The daytime and nighttime PM10 concentration ratios (D/N) for Mg, K, Ca, Cr, Mn, Fe, Zn, Al, Cu, As, and V were in the same order of magnitude, however, the D/N ratios of Cd, Pb, Ni, and Ti in spring and summer varied higher than an order of magnitude, indicating that the emission sources of PM were different in daytime and at nighttime. Correlation analysis of OC and EC showed that OC and EC at nighttime had a higher correlation than those in daytime, while OC and EC had a higher correlation in Kinmen Island than those in metro Xiamen, indicating carbonaceous sources must be different in summer and winter at Xiamen Bay. Enrichment factor analysis revealed that ceramic industry, stone processing, and cement industry had higher correlation with PM10 concentration than utility power plants. Crustal dusts consisted of road dusts, farmland dusts, and constructive dusts, while biomass burning was not a negligible sources. Results obtained from PCA and CMB receptor modeling showed that major sources of PM in Xiamen Bay were secondary inorganic aerosols, fuel and biomass burning, marine aerosols, vehicular exhansts, and soil dusts. Besides, stone processing, cement industry, ceramic industry, and utility power plants had the highest contribution in winter. Their contributions in daytime and at nighttime were 38% and 45%, respectively.

Methane measurements over lake Tämnaren show a pronounced diurnal variation with high values at night and low values during daytime. The atmosphere over the lake and its surroundings is simulated with two different settings and resolutions of the WRF model during a period of eight days in May 2011 to investigate if a lake/land breeze circulation could be the cause of the observed methane variation. A night time land breeze can give rise to convergence over Tämnaren of the natural methane emissions from the lake which possibly could explain the diurnal variation. Analysis show that although Tämnaren is large enough to initiate a fully closed circulation these events are likely going to be rare because of the strong dependence of the background wind speed and cannot therefore be the cause of the pronounced diurnal variation. A fairly moderate wind speed will dominate over the thermodynamical forcing necessary to create a lake breeze. Even so, it is possible that a closed or nearly closed circulation could enhance the diurnal pattern with an increase of methane concentration at night and a decrease during the day. The reason for the high night time methane concentration is more likely due to the accumulation in a shallow internal boundary layer that develops over the lake combined with high night time methane flux caused by waterside convection. / Mätningar av metankoncentrationen över Tämnaren visar en tydlig dygnsvariation med höga värden på natten och låga under dagtid. Atmosfären över sjön med omgivning modelleras med två olika inställningar och upplösningar av WRF modellen under en åttadagarsperiod i Maj 2011 för att undersöka om en sjö- och landbriscirkulation kan vara orsaken till den observerade metanvariationen. På natten kan en landbris ge upphov till konvergens över Tämnaren av de naturliga metanutsläppen vilket skulle kunna vara en möjlig förklaring till dygnsvariationen. Vidare analys visar att Tämnaren är tillräckligt stor för att initiera en sluten cirkulation men dessa händelser är troligtvis sällsynta på grund av det starka inflytandet av bakgrundsvinden och kan därför inte vara orsaken till den uttalade metanvariationen. En relativt måttlig vind kommer dominera över den termodynamiska effekt som är drivande för skapandet av sjö- och landbris. Trots detta är det möjligt att en sluten eller nästan sluten cirkulation kan förstärka metanhaltens dygnsvariation med en ökning på natten och minskning under dagen. Orsaken till den observerade höga metankoncentrationen på natten är troligare en ackumulering i ett grunt internt ytskikt som bildas över Tämnaren kombinerat med höga nattliga metanflöden till följd av konvektion i sjön.

Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat scatterometer and microwave radiometer measurements from the Special Sensor Microwave/Imager (SSM/I) are used to determine periods of surface melt and freeze in the Antarctic ice-shelves. The normalized radar backscatter (sigma-0) and backscatter polarization ratio (PR) are used in the maximum likelihood estimation of the ice-state. This method is used to infer the daily ice-surface conditions for 25 selected study points located on the Ronne, Ross, Larsen, Fimbul, Amery, and Shackleton Ice-shelves. The temporal and spatial variations of the radar response are also observed for various neighborhood sizes surrounding each given point during the study period. Criteria for determining the dates of melt-onset and freeze-up for each Austral summer are also presented. Validation of the ice-state and melt-onset date estimates is performed by analyzing corresponding brightness temperature (Tb) measurements from radiometers. QuikScat sigma-0 measurements from 1999 through 2003 are analyzed and it is shown that Ku-band scatterometers are very useful for determining periods of melt in Antarctic ice-sheets and provide high temporal and spatial resolution ice-state estimates. These estimates can be important for long-term studies of the climatic effects of the seasonal and inter-annual melting of the Antarctic ice-sheets. The SeaWinds on QuikScat (QuikScat) and SeaWinds on ADEOS-2 (SeaWinds) scatterometers are identical radar sensors on different spaceborne platforms traversing similar orbits. QuikSCAT and SeaWinds data are used to infer near-surface wind vectors, polar sea-ice extent, polar-ice melt events, among others. In order to verify the relative calibration of these two sensors a simple cross-calibration method is implemented based on land measurements. A first-order polynomial model for the incidence angle dependence of sigma-0 is used to account for biases in the sigma-0 measurements. This model is applied to selected regions of the Amazon rainforest and the Sahara desert. It is shown that the two sensors are well calibrated. Additionally, evidence of a previously presumed diurnal cycle in the Amazon rainforest backscatter is given.

Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat (QuikScat) and SeaWinds on ADEOS-2 (SeaWinds) scatterometers are used to classify the melt state and estimate melt severity in Greenland. Backscatter measurements are organized into high temporal and high spatial resolution images created using the Scatterometer Image Reconstruction (SIR) algorithm and a new temporal data segmentation technique. Melt detection is performed using a layered electromagnetic model combined with a Markov chain model. The new melt detection method allows classification of the snow-pack into three states: melt, refreeze, and frozen. Melt severity and refreeze severity indexes are also developed. The melt detection methods developed in this thesis are verified by using a one-dimensional geophysical/electromagnetic model simulation of the snow-pack under melting conditions and by comparison with in situ weather station data at the ETH Camp in western Greenland. The diurnal cycle of backscatter measurements is also analyzed at this location. The melt detection and estimation method is applied to the entire Greenland ice-sheet. The resulting melt classifications and melt severity indexes are used to generate a number of maps outlining the features of the 2003 melt season. Good agreement of the melt severity and a 1978 SASS Greenland ice facies map is observed.

The thesis "Four Essays on the Econometric Modelling of Volatility and Durations" consists of four research papers in the area of financial econometrics on topics of the modelling of financial market volatility and the econometrics of ultra-high-frequency data. The aim of the thesis is to develop new econometric methods for modelling and hypothesis testing in these areas. The second chapter introduces a new model, the time-varying GARCH (TV-GARCH) model, in which volatility has a smooth time-varying structure of either additive or multiplicative type. To characterize smooth changes in the (un)conditional variance we assume that the parameters vary smoothly over time according to the logistic transition function. A data-based modelling technique is used for specifying the parametric structure of the TV-GARCH models. This is done by testing a sequence of hypotheses by Lagrange multiplier tests presented in the chapter. Misspecification tests are also provided for evaluating the adequacy of the estimated model. The third chapter addresses the issue of modelling deterministic changes in the unconditional variance over a long return series. The modelling strategy is illustrated with an application to the daily returns of the Dow Jones Industrial Average (DJIA) index from 1920 until 2003. The empirical results sustain the hypothesis that the assumption of constancy of the unconditional variance is not adequate over long return series and indicate that deterministic changes in the unconditional variance may be associated with macroeconomic factors. In the fourth chapter we propose an extension of the univariate multiplicative TV-GARCH model to the multivariate Conditional Correlation GARCH (CC-GARCH) framework. The variance equations are parameterized such that they combine the long-run and the short-run dynamic behaviour of the volatilities. In this framework, the long-run behaviour is described by the individual unconditional variances, and it is allowed to vary smoothly over time according to the logistic transition function. The effects of modelling the nonstationary variance component are examined empirically in several CC-GARCH models using pairs of seven daily stock return series from the S&amp;P 500 index. The results show that the magnitude of such effect varies across different stock series and depends on the structure of the conditional correlation matrix. An important feature of financial durations is the evidence of a strong diurnal variation over the trading day. In the fifth chapter we propose a new parameterization for describing the diurnal pattern of trading activity. The parametric structure of the diurnal component allows the duration process to change smoothly over the time-of-day according to the logistic transition function. The empirical results suggest that the diurnal variation may not always have the inverted U-shaped pattern for the trade durations as documented in earlier studies.

MENVSC (Geography) / Department of Geography and Geo-Information Sciences / Rainfall is undoubtedly the most significant factor for life’s continuity. South Africa is prone to future climate uncertainties due to global climate change. The aim of this study is to investigate rainfall variability and change in South Africa on a present day (1976-2005), near-future (2006-2035) and far-future (2036-2065) climate. For the study, 3 RCMs (REMO2009, RCA4 and CCLM4-8-17), forming part of CORDEX-Africa project were nested within 5 different CIMP5_GCMs of low resolution. GPCC precipitation, NOAA GHCN_CAMS Land Temperature and other NCEP reanalysis products were useful in validating models in simulations of present-day climate. RCP4.5 and RCP8.5 emission scenarios from IPCC-AR5 were used for future climate projections. On the validation, each regional climate model displayed different signature on simulations, rainfall in particular because this is a variable that is affected most by sub-grid process. Simulations nested within MIROC5 simulated more precipitation than simulations forced with other GCMs, due to more large-scale moisture convergence into the nested domain. There were differences in projections of RCM nested within the same GCM, as well as with the same RCM nested within different GCMs, on the future. Models nested within MPI project wetter conditions over the eastern parts of Limpopo, while the other two projected drier conditions in the same area. REMO2009 forced on MPI uniquely projected drying of Western Cape throughout the seasons on both RCPs and futures. Simulations conducted with the RCP8.5 scenario forcing are generally found to be associated with either a larger increase in temperature, or an increase in area associated with higher temperature increases. CCLM4-8-17 forced on HadGEM2 projected below average temperatures over the northwest parts of the country under the RCP8.5 scenarios. MPI driving model projected a general reduction of evaporation values, with lowest over northeast, northwest parts and south coastal parts of South Africa, in contrary to adjacent oceans. In this study, we have sought to identify the sources of uncertainties amongst model simulations between either the RCMs or the driving GCMs. / NRF

Weather radars are increasingly used for the study of clouds, understanding the precipitation systems and also for forecasting very short range weather (one hour to a few hours). Now, Doppler Weather Radar (DWR) data are available in India and it is possible to study cloud properties at fine temporal and spatial scales. Radar is a complex system and calibration of a radar is not an easy job. But derived cloud properties strongly depend on the absolute magnitude of the reflectivity. Therefore, there is a need to check how data from two or more radars compare if they measure a common volume. Chennai and SHAR radars are within 66 km from each other, and the data collected during their calibration and intercomparison experiment in 2006 enables the comparison of their reflectivity(Z) values. Individual reflectivity are compared after plotting SHAR versus Chennai in a scatter plot. Fitting a least square linear best fit line shows that the intercept has a value around 6 dBZ and the slope of the line is 1.06. Thus, there is a trend as well, and the difference between the two radars increase with Z, and for Z around 40 dBZ (for SHAR DWR), the difference between the two is around 8.5 dBZ. Visual intercomparison also validated the results. Data from the two radars are compared with Precipitation Radar (PR) data on board TRMM satellite. TRMM radar slightly overestimates compared to Chennai radar above the range of 30 dBZ. After standardized, SHAR data is used for understanding the evolution and propagation of cloud systems. The diurnal variation in convection is strong in the study region, with increase around local evening and morning and weakening around midnight except in December. Average liquid water content in the clouds is about 0.5 gm/m3. There is some seasonal dependence but no clear dependence on cloud size. Smaller systems of May have more liquid water content compared to larger ones. For nowcasting vertically projected maximum reflectivity is taken. A threshold of 30 dBZ is set to identify the cloud systems. Both center of gravity tracking (CG) and cross-correlation (CC) methods are used to track them. Frequent merging and splitting is common in the clouds which makes storm tracking difficult. Tracking by CC is giving better result than that by the CG method in the case of large systems (i.e., clusters). For smaller systems (individual cloud systems), CC method gives better result than CG method but not as good as cluster.