Analysis Of Long-term Changes Research Articles

On the application and interpretation of Keeling plots in paleo climate research – deciphering δ<sup>13</sup>C of atmospheric CO<sub>2</sub> measured in ice cores

Abstract. The Keeling plot analysis is an interpretation method widely used in terrestrial carbon cycle research to quantify exchange processes of carbon between terrestrial reservoirs and the atmosphere. Here, we analyse measured data sets and artificial time series of the partial pressure of atmospheric carbon dioxide (pCO2) and of δ13C of CO2 over industrial and glacial/interglacial time scales and investigate to what extent the Keeling plot methodology can be applied to longer time scales. The artificial time series are simulation results of the global carbon cycle box model BICYCLE. The signals recorded in ice cores caused by abrupt terrestrial carbon uptake or release loose information due to air mixing in the firn before bubble enclosure and limited sampling frequency. Carbon uptake by the ocean cannot longer be neglected for less abrupt changes as occurring during glacial cycles. We introduce an equation for the calculation of long-term changes in the isotopic signature of atmospheric CO2 caused by an injection of terrestrial carbon to the atmosphere, in which the ocean is introduced as third reservoir. This is a paleo extension of the two reservoir mass balance equations of the Keeling plot approach. It gives an explanation for the bias between the isotopic signature of the terrestrial release and the signature deduced with the Keeling plot approach for long-term processes, in which the oceanic reservoir cannot be neglected. These deduced isotopic signatures are similar (−8.6‰) for steady state analyses of long-term changes in the terrestrial and marine biosphere which both perturb the atmospheric carbon reservoir. They are more positive than the δ13C signals of the sources, e.g. the terrestrial carbon pools themselves (−25‰). A distinction of specific processes acting on the global carbon cycle from the Keeling plot approach is not straightforward. In general, processes related to biogenic fixation or release of carbon have lower y-intercepts in the Keeling plot than changes in physical processes, however in many case they are indistinguishable (e.g. ocean circulation from biogenic carbon fixation).

A Method of Homogenizing the Extremes and Mean of Daily Temperature Measurements

Abstract To be confident in the analyses of long-term changes in daily climate extremes, it is necessary for the data to be homogenized because of nonclimatic influences. Here a new method of homogenizing daily temperature data is presented that is capable of adjusting not only the mean of a daily temperature series but also the higher-order moments. This method uses a nonlinear model to estimate the relationship between a candidate station and a highly correlated reference station. The model is built in a homogeneous subperiod before an inhomogeneity and is then used to estimate the observations at the candidate station after the inhomogeneity using observations from the reference series. The differences between the predicted and observed values are binned according to which decile the predicted values fit in the candidate station’s observed cumulative distribution function defined using homogeneous daily temperatures before the inhomogeneity. In this way, adjustments for each decile were produced. This method is demonstrated using February daily maximum temperatures measured in Graz, Austria, and an artificial dataset with known inhomogeneities introduced. Results show that given a suitably reliable reference station, this method produces reliable adjustments to the mean, variance, and skewness.

Temperature trends in the middle atmosphere as seen by historical Russian rocket launches: Part 1, Volgograd (48.68°N, 44.35°E)

We present a new analysis of long-term changes of temperature using data from a rocketsonde data series obtained at Volgograd (48.68°N, 44.35°E) from January 1969 to September 1995. In this series, temperature measurements exhibit discontinuities due to instrumental changes that need to be taken into account for trend estimates. Also changes of the moment when the measurements were performed can also induce discontinuities associated with the existence of atmospheric tides and bias related to solar elevation angle. Data have been selected according to the hour of the launch and sub-sets of data have been generated in order to identify homogeneous datasets. The trend analysis method used here is based on a multi-function regression analysis that assumes a linear long-term trend superimposed on natural variability. Sudden changes of the calculated mean temperature, potentially induced by discontinuities, have been estimated and taken into account by including step functions in the regression model. This analysis shows a cooling in the middle stratosphere, with magnitude increasing with altitude up to 10–15 K/decade in the upper mesosphere. The results obtained are compared with trend estimates performed earlier for other mid-latitudes data series using the same analysis. It shows a slight increase of the trend with latitude, despite the limited number of sites.

Long-Term Studies of Common Gulls (Larus Canus) in Estonia: Responses to Environmental Conditions

The population of Common Gulls has been studied since 1962, making the analysis of longterm changes in the population and the impact of the changing environment possible. Due to the fixed clutch size, the reproductive lifespan and survival of offspring from hatching to maturity, both affected mainly by winter severity, are the prime creators of the variation in lifetime reproductive success (fitness). We point out that climatic conditions influence both the annual breeding success (hence, fitness) and the age at first breeding through the laying date (early years, late years). However, over the 35 year-long period of studies we have not found any persistent advancement in the laying date. We emphasise that the use of phenotype values in the analysis of natural selection may lead to incorrect results due to phenotypic plasticity. The invasion of Herring Gulls in the middle of the 1970s has caused a 1.3-fold and 3.5-fold increase in natal fidelity of males and females, respectively, resulting in the possibl...

Regional patterns in recent trends in sediment yields of Eurasian and Siberian rivers

A multipurpose hydrological and statistical analysis of long-term changes in suspended sediment yield has been made for large Russian rivers discharging to the Arctic Ocean. Factors affecting sediment yield formation, e.g., snow pack duration, mean air temperature and mean water discharge, have been analyzed as well. The duration of observations at 13 selected meteorological stations varies from 56 to 113 years and covers the period from 1883 to 1995. The duration of water discharge measurements at 22 hydrological stations varies from 20 to 120 years; measurements were made from 1881 to 2000. The duration of sediment yield observations is shorter (from 1936 to 2000) and varies from 14 to 62 years. The air temperature rise is evident for 10 stations while temperature fall is observed at 3 stations (Dickson Island, Narjan Mar, Kiusiur). These three stations are established in the coastal area of the Arctic Ocean. The most impressive coincidence of trends towards an increase of mean air temperature and mean annual water discharge is observed in the Pechora, Angara, Lena, Aldan, Yana and Indugirka river basins, and in the lower reaches of the Ob and Yenisei river basins. A decrease of water discharge is observed in the Severnaya Dvina river, probably refracting by the effect of cut forest on water availability in the river. The decrease of water discharges in the upper parts of the Ob and Yenisei river basins refracts reservoirs. Changes in suspended sediment yield depend more on man's activity than on climate change. Construction of reservoirs in the upper reaches of the Ob and Yenisei rivers explains the decreased sediment yield. An increase of sediment yield in the Kolyma river basin has been observed due to the gold mining there.

Morpho-functional analysis of long-term changes in structure of Cystoseira phytocenosis (Laspy Bay, Black Sea)

Morpho-functional analysis of long-term changes in structure of Cystoseira phytocenosis (Laspy Bay, Black Sea)

The analysis of long-term changes in plant communities: case studies from the Netherlands

The nature of the plant community has been a long-standing point of discussion in vegetation science. Already in the early decades of the last century, debate focused on whether plant communities existed as discrete, intra-dependent entities or merelyas loose assemblages of species each responding individualistically to local environmental conditions. Despite the fundamental nature of this question, the issue is generally ignored in many studies. For example, within the study of succession, a major topic in vegetation science, the question of stability within vegetation types is rarely addressed. Generally, succession research investigates vegetation development in terms of communities passing through a series of vegetation types, without considering the nature of these types; they are implicitly regarded to be constant. To some extent, this idea is a misconception, as can be concluded from studies within the framework of the national vegetation classification of the Netherlands. During this programme, a large data set has been built up, comprising more than 350 000 vegetation releves, made in the period 1929-2001. Comparison of sets of releves from different decades revealed that in most ecosystems the floristic composition of the vegetation types involved has changed, although the appearance of the vegetation and the presence and abundance of (most of) the diagnostic species have remained the same. In the present study, three examples were elucidated: an aquatic vegetation type dominated by Stratiotes aloides (Stratiotetum), a species-rich grassland type on river dunes (Medicagini falcatae-Avenetum pubescentis), and a forest community (Betulo-Quercetum roboris).

Dependence of foF2 long-term changes on solar activity and longitude

The analysis of long-term changes of the F2-layer critical frequency at mid-latitudes was carried out. The additional dependence of quiet monthly median values, foF2m, on sliding average over 11 years of Wolf number values was found. This allowed to isolate a linear on time trend of relative average annual values of foF2 which was not connected significantly to solar action. It is found that this trend is the sum of the trend P on account of the greenhouse effect, which almost does not depend on longitude, and the trend because of secular variations of the geomagnetic field M whose dependence on longitude is essential.

Panel Data in Housing Research: A Reaction to the Paper by Myers on Cohort Longitudinal Estimation of Housing Careers

Both cross-sectional and panel data can be used to analyse the dynamics of housing markets over time. Myers proposes the method of longitudinal cohort analysis of repeated cross-sectional data for the study of trends in housing market circumstances. He emphasises the problems and limitations of the use of panel data for such purposes. In this article it is argued that Myers underestimates the potentials of panel data for the study of housing market dynamics over time. Panel data are now relatively easy to obtain and use, also for the analysis of long-term changes in housing markets. Prices and turnover rates in housing markets have been shown to be strongly auto-correlated across geographical space. Therefore, panel data can be used to analyse regional differences in housing markets, even if these data have a relatively small sample size.

Trajectory analysis of long-term changes in the nutritional status of a Scots pine stand

For the Scots pine (Pinus sylvestris L.) stand Pustert (Bavaria, Germany), the temporal change in its nutritional status as assessed by foliar analysis is analyzed using different techniques of statistical data evaluation and graphical representation. The procedures include new methods such as the development of adequate trajectories and their combination with an improved “Timmer and Stones graphical diagnostic system” as well as with a Principal Component Analysis (PCA). This mothod of data evaluation and presentation has several advantages: (i) It allows to visualize the dynamics of a multi-dimensional data set in two-dimensional graphs. Additionally, (ii) it provides a tool to easily identify various types of temporal changes in tree nutrition as e.g. nutrient insufficiency, luxury consumption, and dilution. Finally (iii), it enables the reader to distinguish quickly between non-systematic inter-annual variation, episodic cyclic changes, and systematic trends in the nutritional status of a forest stand.

Community-level analyses of long-term changes in rocky littoral fauna from South Africa

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 164:47-57 (1998) - doi:10.3354/meps164047 Community-level analyses of long-term changes in rocky littoral fauna from South Africa A. H. Dye* Department of Zoology, University of Transkei, Umtata, Eastern Cape, South Africa 5117 *E-mail: dye@getafix.utr.ac.za Changes in the structure of benthic invertebrate communities in undisturbed and experimentally cleared quadrats on 3 rocky shores on the east coast of South Africa were monitored quarterly for 14 yr from 1982. There were no clear long-term trends in species diversity in either undisturbed or experimentally cleared areas. Diversity decreased and became more variable following disturbance and remained so throughout the study. Fourier analyses revealed significant annual cycles in diversity in undisturbed areas at all sites, while only half of the cleared areas exhibited significant annual cycles. Non-metric multidimensional scaling ordinations, based on Bray-Curtis similarity matrices, were used to represent traces of the 'state' of the community through time at each site. Undisturbed areas typically exhibited 2 or more apparently stable states, persisting for periods exceeding the turnover time of the dominant populations, with brief periods of instability between them. Fluctuations in the abundance of barnacles and periwinkles accounted for most of the differences between these states. The lower balanoid zone community tended to oscillate between states more frequently than that in the upper balanoid zone. Correlations between traces from different sites tended to be stronger for high shore communities than for those lower on the shore. Disturbed communities either converged to a stable state, persisting for more than 10 yr, or remained unstable throughout the study. Similarities in long-term variability between sites suggest the influence of large-scale factors affecting the supply and survival of larvae. Rocky littoral · Community · Long-term variability · Disturbance · Stability Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 164. Publication date: April 09, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.

Evaluation of Long-Term Changes in Radiation, Cloudiness, and Surface Temperature on the Territory of the Former Soviet Union

Regular measurements of solar radiation carried out in the network of actinometric stations of the former Soviet Union (FSU) have shown a decreasing tendency in the time series of direct and global solar radiation during last decades. A statistically significant decrease has been found in 60% of the time series of global radiation annual totals obtained from 160 actinometric stations. Three large areas, where this decrease exceeded 2% per 10 years, were found (in the European part of the FSU, in West Siberia, and in the Far East). As the main reason for changes in solar radiation, increased cloudiness and atmospheric turbidity are considered. A more detailed analysis of long-term changes in radiation budget components obtained from two stations situated in rather different conditions (Moscow Meteorological Observatory in a large town and Tõravere Actinometric Station in a rural area) allows us to point out the influence of a large town as a source of air pollution on the radiation transfer in the atmosphere, as well as on cloudiness and air temperature.

The Deskilling Thesis Revisited: On Peter Armstrong's Defence of Braverman

Peter Armstrong's recent defence of Braverman's deskilling theory argues that most critics misinterpret its logical nature. Consequently, the bulk of empirical research indicating short term changes in skill levels cannot be accepted as disconfirming evidence. Armstrong's argument brings out some overlooked elements in the deskilling thesis and points out important limitations of the studies critical of it. At the same time, Armstrong's clarification of the character of Braverman's theory also exposes some of the problems in the deskilling thesis itself. Armstrong correctly points out the long term, tendential character of the theory but fails to confront some central methodological problems in the study of long term shifts in work skills. This paper looks at three issues which Armstrong's argument raises: i) the nature of a ‘law of motion’ which is claimed to be the logical status of the theory; ii) Braverman's very specific notion of skill; iii) the methodological issues associated with analysis of long term changes in skills. Additionally, I explore the issue of technological change which, I argue, constitutes a ‘relatively autonomous’ source of constraints and pressures on capitalism management, not to be treated as a weapon or outcome in management's struggles to control labour.

Statistical method for selecting representative species in multivariate analysis of long-term changes of marine communities. Applications to a macrobenthic community from the Bay of Morlaix

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 120:243-250 (1995) - doi:10.3354/meps120243 Statistical method for selecting representative species in multivariate analysis of long-term changes of marine communities. Applications to a macrobenthic community from the Bay of Morlaix Manté, C., Dauvin, J.-C., Durbec, J.-P. A new method is presented for analysing biological time series with only a few observations of many species. It operates by selecting the more informative species and describing the temporal changes of a community using a Principal Components Analysis method based on the relative proportions of selected species. The method was tested on a macrobenthic time series data from the Bay of Morlaix (western English Channel). Principal components . Species selection . Time series Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 120. Publication date: April 20, 1995 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1995 Inter-Research.

Has the Gulf War affected coral reefs of the northwestern Gulf?

Surveys of offshore and nearshore reefs in Kuwait and Saudi Arabia were undertaken during the latter part of 1992. A small, inshore platform reef located close to one of the Kuwait sources of the Gulf War oil spill had been partially impacted. However, corals were recovering and it supported a healthy fish community. No evidence of pollution damage was detected on the Saudi Arabian reefs, and a patchy distribution of mortality in three species of coral was found on the offshore Kuwait reefs. Analysis of long term changes in the Kuwait reef fish populations reveal a downward trend in numbers. It is concluded that natural fluctuations in the coral reef community may have effectively masked any supposed impact of the Gulf War, and suggested that only continued monitoring will reveal any longer term Gulf War effects.

Surface ozone and meteorological predictors on a subregional scale

Meteorological conditions affect the ozone concentration near the surface. To quantify the importance of meteorological parameters for the surface ozone concentration a nonlinear regression analysis between 313 meteorological candidate predictors and surface ozone concentration at five stations in the German Democratic Republic over the period 1972–1987 has been made. The stability and quality of the relationship between ozone and meteorological predictors has been tested by independent samples. Most important predictors for surface ozone are the ozone value of the preceding day (persistence) and solar radiation. They explain 33–46% and 6–21% of the climatological ozone variance, respectively. As all meteorological parameters can be forecasted, the regression method described might be the basis for a short-term prediction of surface ozone. An analysis of long-term changes of surface ozone and solar radiation shows that changes in cloudiness are probably not the main cause of the long-term changes in surface ozone. Therefore, the ozone changes should mainly be due to changes in circulation and/or concentration of ozone precursors (NO x , VOC).

Analgzing long-term changes in vegetation with geographic information system and remotely sensed data

Geographic information systems and remote sensing techniques are powerful tools in the analysis of long-term changes in vegetation and land use, especially because spatial information from two or more time intervals can be compared more readily than by manual methods. A primary restriction is the paucity of data that has been digitized from earlier periods. The Illinois State Geographic Information System has a number of automated data sets containing land-use information, including original land survey plat maps that show the boundaries of forests, prairies, and wetlands as they existed prior to European colonization in the early 1800s. More recent data include the United States Forest Service inventories of 1948, 1962, and 1985; the United States Geological Survey Land Use Data Analysis; National High Altitude Program photographs of vegetation; and Landsat MSS and TM information. These data can be used to compare vegetation patterns and changes in land use over time and to suggest factors that may have caused or influenced these variations. Profound changes have occurred in the Illinois landscape since European settlement, primarily because of conversion to agricultural use; in certain parts of the state, however, urbanization has been the major factor contributing to changes.

Long-term changes in the occupational structure

This article is devoted to an empirical analysis of long-term changes in the distribution of the labour force (or employment) by occupation. The literature on the subject is not very extensive. A careful collection of long-term data on the employment structure of several countries, some of which concern occupations, is contained in Bairoch (1968). A statistical study based on cross-sectional and time-series data for 51

Demographic components of growth in white, black, and Puerto Rican female-headed families: Comparison of the Cutright and Ross/Sawhill methodologies

This study examines the methodological differences between Cutright's (1974, Journal of Marriage and the Family 36, 714–721) and Ross and Sawhill's (1975, Time of Transition: The Growth of Families Headed by Women. The Urban Institute, Washington, D.C.) analyses of demographic components of growth in the number of female-headed families and replicates their procedures within a comparable time/age framework in order to resolve their contradictory findings. The analysis suggests that while changes in living arrangements and population are the two major factors accounting for changes in the number of White female-headed families between 1940 and 1970, marital instability is the major factor responsible for the increase in the number of White female-headed families between 1960 and 1970. Cutright's analysis of long-term changes for nonwhites is debatable. The relative importance of demographic factors in explaining the absolute increase in female-headed families between 1960 and 1970 clearly varies by ethnic/racial group.

Social Democracy in Welfare Capitalism – Structural Erosion, Welfare Backlash and Incorporation?

Sweden is here taken as a ‘test case’ for post-war social science theories predicting that changes inclass, stratification and community structures accompanying industrialization will gradually erode the base for socialist voting and make the mobilization of the electorate by the socialist parties more difficult. The maturation of the welfare state has further been predicted to generate a ‘welfare backlash’ against the social democratic parties. An analysis of long-term changes in social structure and socialist voting in Sweden does not give support to these hypotheses. An alternative interpretation is suggested in which the shape and changes in the power structure in society are taken as the starting point for the analysis of the possibilities and limitations for social democratic policies in advanced capitalist society.