Short-term and long-term variation in seed bank/vegetation relations along an environmental and successional gradient

Ecography ◽  
2008 ◽  
Vol 24 (6) ◽  
pp. 731-741 ◽  
Author(s):  
Ulf Grandin
Keyword(s):  
Seed Bank ◽  
Short Term ◽  
Term Variation ◽  
Successional Gradient

scholarly journals Satellites, Self-reports, and Submersion: Exposure to Floods in Bangladesh

2015 ◽  
Vol 105 (5) ◽  
pp. 232-236 ◽  
Author(s):  
Raymond Guiteras ◽  
Amir Jina ◽  
A. Mushfiq Mobarak
Keyword(s):  
Climate Change ◽  
Economic Activity ◽  
Climate Change Impacts ◽  
Objective Data ◽  
Short Term ◽  
Temperature And Precipitation ◽  
Flood Exposure ◽  
Self Reports ◽  
Term Variation

A burgeoning “Climate-Economy” literature has uncovered many effects of changes in temperature and precipitation on economic activity, but has made considerably less progress in modeling the effects of other associated phenomena, like natural disasters. We develop new, objective data on floods, focusing on Bangladesh. We show that rainfall and self-reported exposure are weak proxies for true flood exposure. These data allow us to study adaptation, giving accurate measures of both long-term averages and short term variation in exposure. This is important in studying climate change impacts, as people will not only experience new exposures, but also experience them differently.

scholarly journals The Long-term Variation in the RV Tauri Star U Mon

1995 ◽  
Vol 155 ◽  
pp. 409-410 ◽  
Author(s):  
Karen R. Pollard ◽  
P. L. Cottrell
Keyword(s):  
High Resolution ◽  
Light Curve ◽  
Radial Velocity ◽  
Tauri Star ◽  
Short Term ◽  
Instability Strip ◽  
Term Variation ◽  
Velocity Variations

The RV Tauri stars are semiregular pulsating variables located in the brightest part of the Cepheid II instability strip. They have a characteristic light curve of alternating deep and shallow minima. A subset of the RV Tauri stars (the RVb subclass) exhibit long-term (500 to 2600 day) light and radial velocity variations. Although it is well established that the short-term variations are due to pulsations, the long-term behaviour is not well understood.BVRI photometry and high-resolution spectra of U Mon (the brightest member of the RVb subclass) were obtained at the Mt John University Observatory (MJUO) between 1990 Aug and 1994 May. The light and colour curves obtained clearly show the long-term variation in U Mon (Fig. 1(a) and (b)). The reddest colours occur slightly later than the long-term minimum in the light curve. The short-term light and colour variations are ‘damped’ at the long-term minimum.

A LRFD Code Format for Accounting Long-Term Variation of Multiple Load Effects

2002 ◽  
Author(s):  
Paulo Mauricio Videiro ◽  
Luis Volnei Sudati Sagrilo ◽  
Edison Castro Prates de Lima
Keyword(s):  
Extreme Value ◽  
Structural Components ◽  
Short Term ◽  
Resistance Factors ◽  
Term Variation ◽  
Load And Resistance Factors ◽  
Load Effects ◽  
Code Format ◽  
Multiple Load

This paper proposes a Load and Resistance Factors Design (LRFD) code format for structural components of offshore structures under multiple load effects. This code format accounts for the long-term variation of seastate and the actual correlation between dynamic load effects due to environmental actions. Ultimate limit states are formulated in terms of an Interaction Ratio (IR) random variable, such that the long-term extreme value of IR greater than unity means component failure. The long-term distribution of IR is obtained by combining the distribution of each short-term seastate. The short-term response of the generally nonlinear IR is determined by time domain simulation, taking into account partial load and resistance factors. The IR short-term distribution may be fitted, for instance, by using Rayleigh or Weibull distribution. The main advantages of the proposed code format are: • This code format accounts implicitly and correctly for the actual correlation among all dynamic environmental load processes. • Structural designers have used interaction ratios for a long time. Hence, it is straightforward to evolve from a deterministic stage of looking for IR < 1, as in old Working Stress Design codes, to a code format where the aim is to design structural components with long term IR extreme value < 1. The feasibility of the proposed code format is demonstrated by calibrating partial factors for beam-column cylindrical members based on components of a Floating Production System Semi-submersible hull.

scholarly journals Temporal and spatial analysis of ozone concentrations in Europe based on time scale decomposition and a multi-clustering approach

2019 ◽  
Author(s):  
Eirini Boleti ◽  
Christoph Hueglin ◽  
Stuart K. Grange ◽  
André S. H. Prévôt ◽  
Satoshi Takahama
Keyword(s):  
Time Scale ◽  
Seasonal Cycle ◽  
Clustering Algorithm ◽  
Short Term ◽  
Ozone Concentrations ◽  
Time Period ◽  
Term Variation ◽  
Long Term Trends ◽  
Time Scale Decomposition

Abstract. Air quality measures that were implemented in Europe in the 1990s resulted in reductions of ozone precursors concentrations. In this study, the effect of these reductions on ozone is investigated by analyzing surface measurements of ozone for the time period between 2000 and 2015. Using a non-parametric time scale decomposition methodology, the long-term, seasonal and short-term variation of ozone observations were extracted. A clustering algorithm was applied to the different time scale variations, leading to a classification of sites across Europe based on the temporal characteristics of ozone. The clustering based on the long-term variation resulted in a site type classification, while a regional classification was obtained based on the seasonal and short-term variations. Long-term trends of de-seasonalized mean and meteo-adjusted peak ozone concentrations were calculated across large parts of Europe for the time period 2000–2015. A multi-dimensional scheme was used for a detailed trend analysis, based on the identified clusters, which reflect precursor emissions and meteorological influence either on the inter-annual or the short-term time scale. Decreasing mean ozone concentrations at rural sites and increasing or stabilizing at urban sites were observed. At the same time downward trends for peak ozone concentrations were detected for all site types. The effect of hemispheric transport of ozone can be seen either in regions affected by synoptic patterns in the northern Atlantic or at sites located at remote high altitude locations. In addition, a reduction of the amplitude in the seasonal cycle of ozone was observed, and a shift in the occurrence of the seasonal maximum towards earlier time of the year. Finally, a reduced sensitivity of ozone to temperature was identified. It was concluded that long-term trends of mean and peak ozone concentrations are mostly controlled by precursors emissions changes, while seasonal cycle trends and changes in the sensitivity of ozone to temperature are driven by regional climatic conditions.

scholarly journals Congruence between automatic fish counter data and rod catches of Atlantic salmon (Salmo salar) in Scottish rivers

2005 ◽  
Vol 62 (4) ◽  
pp. 808-817 ◽  
Author(s):  
J.L. Thorley ◽  
D.M.R. Eatherley ◽  
A.B. Stephen ◽  
I. Simpson ◽  
J.C. MacLean ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Spatial Scales ◽  
Short Term ◽  
Atlantic Salmon Salmo Salar ◽  
Residual Variation ◽  
Term Variation ◽  
Temporal And Spatial ◽  
Counter Data

Abstract The potential utility of rod catch and automatic fish counter data as measures of Atlantic salmon (Salmo salar) abundance in Scottish rivers was assessed. The trend (long-term) and residual (short-term) variation in the net annual count for 12 counters were compared with the trend and residual variation in either the annual or spring (February–May) rod catch, as appropriate, for the fisheries district in which the counter is located. Trends were fitted using a cubic smoothing spline and compared using reference bands. In eight of the 12 short-term comparisons, the residuals were significantly correlated. The four incongruent short-term comparisons involved the shortest time-series (≤12 years) or lowest rod catches. In eight of the 12 long-term comparisons, the trends fell within the reference bands in 50% or more of the years. Rod catch and counter data both contain useful information about Atlantic salmon abundance, albeit on different temporal and spatial scales, which should be integrated into assessment schemes.

scholarly journals An analysis of the long-term variation in stream water quality for three upland catchments at Loch Dee (Galloway, S.W. Scotland) under contrasting land management

2004 ◽  
Vol 8 (3) ◽  
pp. 422-435 ◽  
Author(s):  
S. J. Langan ◽  
D. Hirst
Keyword(s):  
Water Quality ◽  
Land Management ◽  
Stream Water ◽  
Base Flow ◽  
Sea Salt ◽  
Stream Water Quality ◽  
Short Term ◽  
Term Variation ◽  
The Impact

Abstract. A long term record of water chemistry, consisting of twenty years of weekly spot samples, from three sub-catchments draining into a loch and the loch outflow in Galloway, S.W. Scotland have been analysed. The analysis undertaken consisted of a three component statistical trend model. The technique allows the identification of long-term, seasonal and short-term trends, as well as differentiation between base flow and high flow responses. The land usage in the three sub-catchments is moorland, forest and forest plus lime. The results show that, since the mid-1980s, there has been a gradual decline in stream-water sulphate of the same order as reductions in the deposition of non-marine sulphate. Superimposed on this trend are somewhat random but considerable perturbations to this decline, caused by sea-salt deposition. There is no evidence of changes in surface water nitrate concentrations. The influence of different land management is evident in the sulphate, nitrate and pH data, whilst variations in calcium concentrations are also a product of differences in hydrological routing and the impact of sea-salt episodes. Keywords: trend analysis, acid deposition, land management, water quality, sea-salts, Galloway, S.W. Scotland

scholarly journals Gear-Type Glide-Meter as an Instrument For Forecasting Full-Depth Avalanches

1980 ◽  
Vol 26 (94) ◽  
pp. 521-521
Author(s):  
Yutaka Yamada
Keyword(s):  
Relative Frequency ◽  
Field Measurements ◽  
Short Term ◽  
Term Variation ◽  
Long Term Variations ◽  
Angle Of Rotation

AbstractThis paper is concerned with the variation of snow glide and its predictability in full-depth avalanches. From field measurements of snow glide using a newly developed gear-type glide-meter which is fixed to the ground and which measures the amount of glide as the angle of rotation of a gear, the following characteristics are deduced: (1) the variation of gliding rate is composed of both short-term and long-term variations, and (2) the existence of correlation between the short-term variation and the relative frequency of avalanches is recognized.

Three Types of South Pacific Subtropical Mode Waters: Their Relation to the Large-Scale Circulation of the South Pacific Subtropical Gyre and Their Temporal Variability

2007 ◽  
Vol 37 (10) ◽  
pp. 2478-2490 ◽  
Author(s):  
Takamasa Tsubouchi ◽  
Toshio Suga ◽  
Kimio Hanawa
Keyword(s):  
World Ocean ◽  
South Pacific ◽  
Recirculation Region ◽  
The South ◽  
Short Term ◽  
The West ◽  
The North ◽  
Term Variation ◽  
North And South

Abstract A detailed spatial distribution of South Pacific Subtropical Mode Water (SPSTMW) and its temporal variation were investigated using the World Ocean Atlas (WOA) 2001 climatology and high-resolution expendable bathythermograph (HRX) line data. In the WOA 2001 climatology, SPSTMW can be classified into western and eastern parts. A detailed examination of spatial distributions using HRX-PX06 line data revealed that the eastern part can be further divided into two types by the Tasman Front (TF) extension. Consequently, SPSTMW can be classified into three types, referred to in the present study as the West, North, and South types. The West type, situated in the recirculation region of the East Australia Current (EAC), has a core layer temperature (CLT) of about 19.1°C; the North type, in the region north of the TF extension, has a CLT of about 17.6°C; and the South type, in the region south of the TF extension, has a CLT of about 16.0°C. The long-term (>6 yr) variations in the inventories of the three types were dissimilar to each other. The short-term (<6 yr) and long-term variations in the mean CLT of the North and South types were greater than that of the West type. Winter cooling in the previous year may have influenced the short-term variation in the South-type CLT. Moreover, the strength of the EAC may have influenced long-term variation in the West-type inventory and thickness and in the North-type thickness and CLT.

Sign in / Sign up

Export Citation Format

Share Document