THE CONCEPT OF AUTOCYCLIC AND ALLOCYCLIC CONTROLS ON SEDIMENTATION AND STRATIGRAPHY, EMPHASIZING THE CLIMATIC VARIABLE

2003 ◽  
pp. 13-20 ◽  
Author(s):  
C. BLAINE CECIL
Keyword(s):  
Climatic Variable

Colorimetric analysis of the dorsal plumage of the red-eyed vireo (Aves: Vireonidae) in Canada

1971 ◽  
Vol 49 (3) ◽  
pp. 417-419 ◽  
Author(s):  
Jon C. Barlow ◽  
Nikki Williams
Keyword(s):  
Boreal Forest ◽  
Test Procedure ◽  
Sums Of Squares ◽  
Climatic Variable ◽  
Colorimetric Analysis ◽  
Dominant Wavelength ◽  
Simultaneous Test ◽  
Character Variation ◽  
Recording Spectrophotometer ◽  
East West

The red-eyed vireo is widely distributed across Canada in the boreal forest. Collections were made at seven localities from central Alberta to central Quebec and potential variation in the olive-green dorsal plumage was analyzed with a recording spectrophotometer equipped with a reflectance attachment. The trichromatic coefficients x (dominant wavelength) and y (purity) and Y (the percentage luminous reflection or brightness) were subjected to an overall analysis of variance, and means were treated with Gabriel's sums of squares simultaneous test procedure. Significant differences were demonstrated among locality samples for Y and x but the STP revealed discordant variation among locality samples, i.e. no east–west clines in character variation were shown. Regressions of Y and x on precipitation were nearly significant and could suggest a weak clinal relationship between color and this climatic variable as predicted by the ecogeographic rule of Gloger.

The relationship between environmental conditions and activity of the giant barred frog (Mixophyes iteratus) on the Coomera River, south-east Queensland

2007 ◽  
Vol 55 (2) ◽  
pp. 89 ◽  
Author(s):  
Amelia J. Koch ◽  
Jean-Marc Hero
Keyword(s):  
Population Density ◽  
Leaf Litter ◽  
Radio Telemetry ◽  
Climatic Conditions ◽  
Lower Number ◽  
Cold Weather ◽  
Activity Levels ◽  
Climatic Variable ◽  
Individual Activity ◽  
The Relationship

Determining the population density of ectotherms is often confounded by individual activity levels, which are highly dependent on ambient climatic conditions. In this study we used radio-telemetry and streamside surveys to examine the influence of local climatic conditions on individual activity levels (detectability) and streamside density of a population of endangered giant barred frog (Mixophyes iteratus) along the Coomera river in south-east Queensland. Temperature was the most important climatic variable influencing the behaviour and hence detectability of M. iteratus. The results indicated that males bury under the leaf litter during cold conditions (<18°C) so fewer were detected during surveys. Although females were also found to bury under the leaf litter in cold weather, no significant relationship between exposure and streamside density was detected. This is likely to be due to the lower number of females detected during surveys. The streamside density of juveniles was significantly related to temperature and rainfall, but little of the variance in the data was explained by climatic conditions, despite greater numbers of juveniles being found than adults. These results indicate that, for increased efficiency, surveys of Mixophyes iteratus should be undertaken when temperatures exceed 18°C.

scholarly journals Critical minimum temperature limits xylogenesis and maintains treelines on the Tibetan Plateau

2016 ◽  
Author(s):  
Xiaoxia Li ◽  
Eryuan Liang ◽  
Jozica Gricar ◽  
Sergio Rossi ◽  
Katarina Cufar ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Minimum Temperature ◽  
The Tibetan Plateau ◽  
Climatic Variable ◽  
Eastern Tibetan Plateau ◽  
Growing Seasons ◽  
Tree Ring Data ◽  
Xylem Growth ◽  
Ecological Mechanisms

ABSTRACTPhysiological and ecological mechanisms that define treelines are still debated. It is suggested that the absence of trees above the treeline is caused by the low temperature that limits growth. Thus, we raise the hypothesis that there is a critical minimum temperature (CTmin) preventing xylogenesis at treeline. We tested this hypothesis by examining weekly xylogenesis across three and four growing seasons in two natural Smith fir (Abies georgei var. smithii) treeline sites on the south-eastern Tibetan Plateau. Despite differences in the timing of cell differentiation among years, minimum air temperature was the dominant climatic variable associated with xylem growth; the critical minimum temperature (CTmin) for the onset and end of xylogenesis occurred at 0.7±0.4 °C. A process-based-modeled chronology of tree-ring formation using this CTmin was consistent with actual tree-ring data. This extremely low CTmin permits Smith fir growing at treeline to complete annual xylem production and maturation and provides both support and a mechanism for treeline formation.

scholarly journals Hubungan Iklim Terhadap Produksi Serta Pendapatan Petani Karet di Kabupaten Padang Lawas Utara

2019 ◽  
Vol 1 (1) ◽  
pp. 56-67
Author(s):  
Irwansyah Nasution ◽  
Tumpal H.S. Siregar ◽  
Erwin Pane
Keyword(s):  
Rainy Season ◽  
Dry Season ◽  
Climate Variables ◽  
Climatic Variable ◽  
Climate Variable ◽  
The Difference ◽  
Relationship Of ◽  
Farmer Income ◽  
The Relationship ◽  
Rainy Days

This study examines the relationship of Climate Variables with Rubber Yield And Farmer Income In Three Subdistricts of Padang Lawas Utara.  This study aims to (1) to determine the effect of climate variable to rubber yield and, (2) To know the difference of farmer's income in rainy season and dry season. This research was conducted in March until May 2017. The result of research is climatic variable especially rainfall and rainy day very significant for influential  rubber yields in Three Subdistricts in Padang Lawas Utara. This may indicate that increasing rainfall amounts with higher rainy days cause a decrease in tapping days resulting in reduction of rubber productivity. There results also showed that farmers' income in rainy season difference in dry season whereas farmer income in dry season is higher than rainy season

scholarly journals The Vegetation–Climate System Complexity through Recurrence Analysis

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 559
Author(s):  
Andrés F. Almeida-Ñauñay ◽  
Rosa María Benito ◽  
Miguel Quemada ◽  
Juan Carlos Losada ◽  
Ana M. Tarquis
Keyword(s):  
Cross Correlation ◽  
Temporal Dynamics ◽  
Vegetation Indices ◽  
Climatic Variable ◽  
Recurrence Plots ◽  
Short Term ◽  
Temperature And Precipitation ◽  
Cross Correlation Analysis ◽  
Mediterranean Grasslands ◽  
Cross Correlations

Multiple studies revealed that pasture grasslands are a time-varying complex ecological system. Climate variables regulate vegetation growing, being precipitation and temperature the most critical driver factors. This work aims to assess the response of two different Vegetation Indices (VIs) to the temporal dynamics of temperature and precipitation in a semiarid area. Two Mediterranean grasslands zones situated in the center of Spain were selected to accomplish this goal. Correlations and cross-correlations between VI and each climatic variable were computed. Different lagged responses of each VIs series were detected, varying in zones, the year’s season, and the climatic variable. Recurrence Plots (RPs) and Cross Recurrence Plots (CRPs) analyses were applied to characterise and quantify the system’s complexity showed in the cross-correlation analysis. RPs pointed out that short-term predictability and high dimensionality of VIs series, as well as precipitation, characterised this dynamic. Meanwhile, temperature showed a more regular pattern and lower dimensionality. CRPs revealed that precipitation was a critical variable to distinguish between zones due to their complex pattern and influence on the soil’s water balance that the VI reflects. Overall, we prove RP and CRP’s potential as adequate tools for analysing vegetation dynamics characterised by complexity.

scholarly journals Litterfall and Nutrient Return in Eucalyptus dunnii Maiden in the Pampa Biome, Brazil

2019 ◽  
Vol 11 (5) ◽  
pp. 362
Author(s):  
Dione Richer Momolli ◽  
Mauro Valdir Schumacher ◽  
Márcio Viera ◽  
Aline Aparecida Ludvichak ◽  
Claudiney do Couto Guimarães ◽  
...  
Keyword(s):  
Organic Matter ◽  
Climatic Variable ◽  
Nutrient Return ◽  
Pampa Biome ◽  
Eucalyptus Dunnii

The objective of this study was to evaluate litterfall and nutrient return in a Eucalyptus dunnii Maiden stand in the Pampa Biome. Four plots were established and four litter collectors per plot were distributed systematically with an area of 0.5 m&sup2; and four subplots used to collect large branches of &gt; 0.5 cm diameter. The collections were carried out biweekly with monthly chemical analyzes over 12 months. The annual litterfall was 8.48 Mg ha-1, of which 59% was composed of leaves. In general, the leaves had the highest macronutrient contents except for Mg. The total macronutrient return was 215 kg ha-1, in the following order: Ca &gt; N &gt; K &gt; Mg &gt; S &gt; P, with the leaves responsible for the return of 73% of the total. The litter represented an important source of organic matter and nutrients, and temperature is the climatic variable that best explains the pattern of production.

scholarly journals Estimating extreme dry spell risk in Ichkeul Lake Basin (Northern Tunisia): a comparative analysis of annual maxima series with a Gumbel distribution

2020 ◽  
Vol 383 ◽  
pp. 241-248
Author(s):  
Majid Mathlouthi ◽  
Fethi Lebdi
Keyword(s):  
Daily Precipitation ◽  
Gumbel Distribution ◽  
Lake Basin ◽  
Climatic Variable ◽  
Rainfall Events ◽  
Northern Tunisia ◽  
Dry Spell ◽  
Ichkeul Lake ◽  
Threshold Amount ◽  
Annual Maximum Series

Abstract. This paper analyses a 42 year time series of daily precipitation in Ichkeul Lake Basin (northern Tunisia) in order to predict extreme dry-spell risk. Dry events are considered as a sequence of dry days separated by rainfall events from each other. Thus the rainy season is defined as a series of rainfall and subsequent dry events. Rainfall events are defined as the uninterrupted sequence of rainy days, when at last on one day more than a threshold amount of rainfall has been observed. A comparison of observed and estimated maximum dry events (42 year return period) showed that Gumbel distribution fitted to annual maximum series gives better results than the exponential (E) distribution combined with partial duration series (PDS). Indeed, the classical Gumbel approach slightly underestimated the empirical duration of dry events. The AMS–G approach was successfully applied in the study of extreme hydro-climatic variable values. The results reported here could be applied in estimating climatic drought risks in other geographical areas.

SIMULTANEOUS THREE CLIMATIC VARIABLE PREDICTIONS IN A GREENHOUSE

2008 ◽  
pp. 157-162 ◽  
Author(s):  
R. Salazar Moreno ◽  
A. Rojano Aguilar ◽  
U. Schmidt ◽  
C. Huber
Keyword(s):  
Climatic Variable

scholarly journals Assessing the Significance of Changes in ENSO Amplitude Using Variance Metrics

2014 ◽  
Vol 27 (13) ◽  
pp. 4911-4922 ◽  
Author(s):  
T. Russon ◽  
A. W. Tudhope ◽  
G. C. Hegerl ◽  
A. Schurer ◽  
M. Collins
Keyword(s):  
Time Series ◽  
Spectral Properties ◽  
Parametric Form ◽  
Climatic Variable ◽  
Central Pacific ◽  
P Values ◽  
Testing Strategies ◽  
Sampling Distributions ◽  
Parametric Testing ◽  
Interannual Anomaly

The variance of time series records relating to ENSO, such as the interannual anomalies or bandpass filtered components of equatorial Pacific SST indices, provides one approach to quantifying changes in ENSO amplitude. Robust assessment of the significance of changes in amplitude defined in this way is, however, hampered by uncertainty regarding the sampling distributions of such variance metrics within an unforced climate system. The present study shows that the empirical constraints on these sampling distributions provided by a range of unforced CGCM simulations are consistent with the expected parametric form, suggesting that standard parametric testing strategies can be robustly applied, even in the case of the nonlinear ENSO system. Under such an approach, the sampling distribution of unforced relative changes in variance may be constrained by a single parameter τd: the value of which depends on the choice of method used to extract the ENSO-related component of time series variability. In the case of interannual anomaly records, the value of τd is also substantially dependent on the overall spectral properties of the climatic variable under consideration. In contrast, the τd value for bandpass filtered records can be conservatively constrained from the lower edge of the filter passband, allowing for the direct but robust assessment of the significance of relative changes in ENSO amplitude, regardless of the climatic variable under consideration. Example applications of this approach confirm marginally significant F-test p values for multidecadal changes in central Pacific instrumental SST variance and highly significant ones for centennial changes in central Pacific coral δ18O variance.

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