Amplitude Of Seasonal Variation Research Articles

Stratospheric ozone profiles based on the EXOS-C satellite data

Monthly and zonal average distributions of ozone in a meridional plane were obtained using the UV spectrometer data on the EXOS-C satellite during March 1984 – September 1987. Individual vertical ozone profiles retrieved from the measured spectral intensities of the backscattered UV was proved to be in general agreement within ±10% with those from ground-based measurements. The EXOS-C meridional ozone distributions are constracted and compared with those of the CIRA model to exhibit an agreement within ±10% on the average in the atmospheric pressure range of 15 – 1.5 mb (altitudes between ≈28 km and ≈45 km). At altitudes above ≈50 km, the EXOS-C ozone volume mixing ratios are systematically smaller than those of the CIRA. This difference can be attributed to a calibration bias. Amplitudes of seasonal variations in ozone volume mixing ratios are also obtained at various latitudes and atmospheric pressure levels and compared with those of the CIRA.

Seasonal variation of growth in body weight of Japanese children and its relationship to physique.

The present study examined the pattern and amplitude of seasonality of growth in body weight of Japanese children living in Tokyo, and analyzed the relationship between physique and seasonal variation. The body weights of 125 school children were measured monthly for 6 years (excluding August). The data were analyzed by time-series analysis. Significant seasonal variations were observed in about 80% of the children. Although individual seasonal patterns and amplitudes varied among children, minimum seasonal factors generally appeared in the Summer. Seasonal variations of group means of body weight were significant in both sexes. The seasonal pattern in boys was low in the Summer and high in the Fall and Winter. Deceleration of weight growth in the Summer was observed in both sexes, even though there were no major stresses in the Summer. The amplitudes of seasonal variation were 1.2% for body weight in boys and 0.7% in girls. In addition, children who were high on the BMI or Rohrer's index had larger amplitudes of seasonal variation, even when body weight of each child was taken into consideration. © 1994 Wiley-Liss, Inc.

体重発育における季節変動とその地域性に関する研究

The monthly body weight data of school children in different regions, the school A in urban area of Tokyo, the school B and C in rural areas of Gunma and Tochigi prefectures, were investigated in order to compare the regional patterns of seasonal variation in weight growth. The seasonal factors of each region and those of each children were calculated by a time-series analysis. The results obtained were as follows. 1) In all regional groups, the highly significant seasonality (p<0.0001) were observed. The seasonal patterns of low in summer, especially in July, were the same in all regional groups. However, the months in which the high values appeared were different among the groups. The amplitudes of seasonal variation were smaller in the children of school A than in the children of school B or C. 2) From the analysis of the seasonal patterns of each child, the minimum values in seasonal factor appeared in July in many children, and it was remarkable in the children of school B and C. 3) The effects of months on variation in weight growth were different between sexes, from the fact that the F-values in the stable seasonality test were much higher in boys than in girls.

Stratospheric ozone profiles based on the EXOS-C satellite data

Monthly and zonal average distributions of ozone in a meridional plane were obtained using the UV spectrometer data on the EXOS-C satellite during March 1984 – September 1987. Individual vertical ozone profiles retrieved from the measured spectral intensities of the backscattered UV was proved to be in general agreement within ±10% with those from ground-based measurements. The EXOS-C meridional ozone distributions are constracted and compared with those of the CIRA model to exhibit an agreement within ±10% on the average in the atmospheric pressure range of 15 – 1.5 mb (altitudes between ∼28 km and ∼45 km). At altitudes above ∼50 km, the EXOS-C ozone volume mixing ratios are systematically smaller than those of the CIRA. This difference can be attributed to a calibration bias. Amplitudes of seasonal variations in ozone volume mixing ratios are also obtained at various latitudes and atmospheric pressure levels and compared with those of the CIRA.

Elemental composition of two coexisting Daphnia species during the seasonal course of population development in Lake Constance.

In 1986 and 1987 the seasonal course of population density, life history traits and biomass composition (CHN-elemental and ash) of two coexisting Daphnia species from L. Constance (Überlinger See) were studied. The two daphnids are morphologically similar, but demonstrate different seasonal variation of behaviour (i.e. diurnal vertical migration). With the exception of nitrogen content, the mean biomass composition of adults and that of eggs were significantly different: the dry biomass of eggs (adults) contained on average 55.6 (46.1) % C, 7.9 (6.5) % H, 9.7 (9.7) % N, and 10.0 (23.8) % ash. These values were similar to those of other daphnids; it may be concluded that the average daphnid composition is not species specific, but is determined mainly by the position in the life cycle and by the nutritional state of the animal. A distinct seasonal variation in the elemental composition of the biomass of adult daphnids was observed. It related significantly to the concentration of food, as indicated by the epilimnetic chlorophyll-a concentrations and by Secchi depth. From the amplitude of seasonal variation of elemental composition and from the shape of relationships between the elemental composition of daphnids and their food, it can be concluded that in summer the non-migrating D. galeata lives under stronger food limitation than the migrating H. hyalina. In spring, there were no differences in the biomass composition of either species. In summer, the adult fcmales of D. galeata contained significantly less carbon, and hydrogen than those of D. hyalina. In most parameters of biomass (i.e. biomass composition of adults) and of life history (i.e. clutch size, mean adult weight), D. galeata displayed higher coefficients of variation. A tendency in D. galeata to have peaks of population development carlier in the season and in D. hyalina to have them towards autumn was observed. These contrasting responses of the populations development, the seasonal variability of the biomass composition seem to support the view of Geller (1986) who called D. galeata and D. hyalina "exploitative" and "conservative" strategists respectively.

Variability of Kuroshio velocity assessed from the sea-level difference between Naze and Nishinoomote

Variations of current velocity of the Kuroshio are examined using the 1965–1983 sea-level difference between Naze and Nishinoomote, located on the offshore and onshore sides of the Kuroshio in the Tokara Strait south of Kyushu. Interannual variations of Kuroshio velocity are large, especially at periods longer than five years and around 2.1 years. They are almost determined by those of sea level on the offshore side of the Kuroshio. They are highly coherent with the offshore sea level at periods longer than 1.7 years, and incoherent with the onshore sea level at periods longer than 2.8 years. The mean seasonal variation averaged for 19 years is at its maximum in July and at its minimum in the second half of October, with a sharp decrease in August and September. However, such a variation does not repeat every year. Amplitude, dominant period and phase are greatly different by year, and they can be roughly divided into four groups: small-amplitude group, semiannual-period group, and two annual-period groups with different phases. The only feature found in almost all years is a weak velocity from September to December. The amplitude of seasonal variation tends to be large in the formation years of the large meander (LM) of the Kuroshio and small during the LM period. It is also large in the years preceding El Nino, and diminishes remarkably in El Nino years. Kuroshio velocity in the Tokara Strait is incoherent with position of the Kuroshio axis over the Izu Ridge, but highly coherent with 70-day variations of coastal sea levels which are dominant during the LM period.

Evolution of Variegated Glacier, Alaska, U.S.A., Prior to its Surge

AbstractDuring the decade prior to its 1982–83 surge, Variegated Glacier experienced progressive changes in geometry and velocity. It thickened in the upper 60% and thinned in the lower 40% of its 20 km length. Thickness changes were up to 20%. Annual velocity increased by up to 500%, reaching a maximum of 0.7 m d−1 in the year before surge onset. Amplitude of seasonal variation in velocity increased up to 0.3 m d−1 by 1978, but did not increase markedly after that. The changes in velocity were larger than predicted from changes in deformation rate caused by changes in shear stress and depth. This anomalous velocity was especially large after 1978 in the zone of thickening on the upper glacier. If it is assumed to arise from basal sliding, the inferred pattern of sliding shows qualitative features consistent with a direct effect from basal shear stress and an inverse effect from effective normal stress. A drop in effective normal stress in a zone of decreasing surface slope up-glacier from the largest thickness increase may have been significant in the initiation of surge motion in 1982.

Evolution of Variegated Glacier, Alaska, U.S.A., Prior to its Surge

Abstract During the decade prior to its 1982–83 surge, Variegated Glacier experienced progressive changes in geometry and velocity. It thickened in the upper 60% and thinned in the lower 40% of its 20 km length. Thickness changes were up to 20%. Annual velocity increased by up to 500%, reaching a maximum of 0.7 m d−1 in the year before surge onset. Amplitude of seasonal variation in velocity increased up to 0.3 m d−1 by 1978, but did not increase markedly after that. The changes in velocity were larger than predicted from changes in deformation rate caused by changes in shear stress and depth. This anomalous velocity was especially large after 1978 in the zone of thickening on the upper glacier. If it is assumed to arise from basal sliding, the inferred pattern of sliding shows qualitative features consistent with a direct effect from basal shear stress and an inverse effect from effective normal stress. A drop in effective normal stress in a zone of decreasing surface slope up-glacier from the largest thickness increase may have been significant in the initiation of surge motion in 1982.

Seasonal variations of water temperature and salinity in Osaka Bay

The characteristics of seasonal variations of water temperature, salinity and density in the upper, middle and lower layers in Osaka Bay are described. Osaka Bay is considered to be an estuary, because the weak mixed state appears in spring and summer and the moderate mixed state in autumn and winter. Osaka Bay is divided into three areas, the eastern shallow area that has a large amplitude of seasonal variation of water temperature and low average salinity, the southwestern deep area which has small amplitude of seasonal variation of water temperature and high average salinity, and the northwestern deep area, which has small amplitude of seasonal variation of water temperature and low average salinity.

Seasonal variation of water temperature in the Seto Inland Sea

The seasonal variation of water temperature in the Seto Inland Sea, Japan is examined using data analysis and numerical experiments and is shown to be controlled by heat exchange through the sea surface and horizontal heat dispersion from the Pacific Ocean. The average water temperature goes down from the Pacific Ocean to the center of the Seto Inland Sea indicating that 4.0 to 6.0×1015 cal day−1 (1.6 to 2.5×1016 joule day−1) of heat is transported from the Pacific Ocean to the Seto Inland Sea and is lost through the sea surface. The amplitude of seasonal variation of water temperature is large at the center of the Seto Inland Sea and the maximum water temperature is reached first at Bisan Straits and last at Iyo-Nada.

A Quantitative Analysis of Shoot Phenology and Dominance in Herbaceous Vegetation

SUMMARY (1) Variation in standing crop and in litter has been measured by seasonal sampling and sorting of the herbaceous vegetation at thirteen sites in the Sheffield region. The vegetation types examined comprised tall herb, woodland floor and grassland communities. At each site the living fraction in 4-10 replicated 0 25 m2 quadrats was separated into its components, and graphs were plotted showing the shoot phenology of the more common species. (2) At the sites in which herbaceous vegetation was growing under fertile, relatively undisturbed conditions, there was a large peak in standing crop during the summer ( > 400 g m- 2 dry weight), and the vegetation contained few species. The low speciesdensities at these sites appeared to be related to the ability of certain species to exercise competitive dominance, a phenomenon involving the rapid expansion of a dense leaf canopy during the period June-August, coupled with the production of a high density of persistent litter. (3) In the woodland and grassland sites examined, the sum of the maximum standing crop and the litter did not exceed 800 g m- 2, and a variety of plant phenologies was encountered. At two of the woodland sites vernal species were prominent; these plants exhibited truncated periods of shoot growth, which preceded full expansion of the tree canopy and followed immediately the marked decline in density of tree litter in early spring. (4) At the sites where the standing crop was severely restricted by low soil fertility, the commonest phenological pattern was that of the evergreen; in certain of these species, no seasonal peak of shoot expansion could be detected. In two of the limestone grasslands investigated, forbs with mid-summer peaks of shoot expansion were prominent; the majority of these plants had relatively deep root-systems, and appeared to exploit reserves of moisture during periods when many grasses were subjected to desiccation. (5) A consistent feature of the results was the marked amplitude of seasonal variation in the abundance of bryophytes, expansion of which coincided with the moist, cool conditions of spring and autumn. (6) A general conclusion drawn from this study relates to the control of speciesdensity in herbaceous vegetation. The results suggest that the potential for high species-density corresponds approximately to the range of 350-750 g m-2 in the sum of maximum standing crop and litter.

A test for seasonality of events with a variable population at risk.

A statistical significance test to detect seasonality of epidemiological events is described. The method is similar to that of Edwards, but makes it possible to allow for an arbitrary pattern of variation in the population risk, and also for the unequal lengths of time sectors of a cycyle of seasons (e.g., months of a year). From the test it is possible to estimate the amplitude of seasonal variation and the time at which the maximum occurs in a postulated simple harmonic fluctuation; the adequacy of the description of the data by a curve of this kind may be evaluated using a goodness-of-fit test. A numerical example of the calculations is given using some anencephalus data, and the results are compared with those of alternative tests.