Climate and intraannual density fluctuations in Pinus pinaster subsp. mesogeensis in Spanish woodlands

2009 ◽  
Vol 39 (8) ◽  
pp. 1557-1565 ◽  
Author(s):  
Stella Bogino ◽  
Felipe Bravo
Keyword(s):  
Pinus Pinaster ◽  
Radial Growth ◽  
Sampling Site ◽  
Woody Species ◽  
Ground Level ◽  
Density Fluctuations ◽  
Climate Change Scenarios ◽  
East Central ◽  
Cambial Age ◽  
The Mean

Intraannual features or anomalies in the tree rings of woody species may provided useful information for ecological and climatological studies. The frequency of intraannual density fluctuations (IADFs), differences in IADFs according to the cambial age, changes in IADFs in the last century, and relationships of IADFs to radial growth and climate were analyzed in five stands of Pinus pinaster subsp. mesogeensis (Fieschi & Gaussen) Silba in east-central Spain. Standard dendrochronological techniques were used. Two cores were extracted 1.30 m above ground level from 15 dominant and codominant trees at each sampling site. The data were analyzed by analysis of variance, Pearson’s correlation, and logistic regression. Results showed that (i) the mean frequency of IADFs was higher in younger than older trees; (ii) the frequency of IADFs increased from the 1940s to the present; (iii) radial growth was negatively correlated with the presence of IADFs; and (iv) density fluctuations may be predicted by using a logistic model, with monthly rainfall and temperature as independent variables. Studies of intraannual features or anomalies in radial growth may be useful for ecological and climatological applications under forecasted climate change scenarios.

scholarly journals High Terrestrial Radiation Level in an Active Tin-Mine at Jos South, Nigeria

2020 ◽  
Vol 24 (3) ◽  
pp. 435-442 ◽  
Author(s):  
M. Atipo ◽  
O. Olarinoye ◽  
B. Awojoyogbe ◽  
M. Kolo
Keyword(s):  
Gamma Radiation ◽  
Dose Rate ◽  
Technological Development ◽  
Absorbed Dose ◽  
Ground Level ◽  
Absorbed Dose Rate ◽  
Lifetime Cancer Risk ◽  
Radiation Level ◽  
Background Gamma Radiation ◽  
The Mean

Mineral mining and milling can be a source of national economic and technological development. However, mining of minerals has been confirmed to disturb the natural distribution of radioisotopes in the soil, air and water bodies in the biota. In an attempt to evaluate the radiological burden resulting from tin mining activities at Rayfield-Du area of Jos, the background gamma-radiation level in the mine was measured via a well calibratedhand-held dosimeter placed at 1 m above ground level. The mean absorbed dose rate, annual effective dose rate and excess lifetime cancer risk for the mine was 0.83 μSvh-1; 1.44 mSv-1 and 0.005 respectively. Generally, dose rates were higher in the mine pits and processing areas as compared to administrative areas of the mine. The mean measured dose rate and calculated dose parameters for the mine were all high when compared to the regulatory limit for public exposure. The potential of developing radiation-induced health defects as a result of high radiation absorbed dose rate by the miners and dwellers around the mine is highly probable.  Keywords: Gamma-radiation; mine; absorbed dose rate; radiation exposure.

scholarly journals Reduced global warming from CMIP6 projections when weighting models by performance and independence

2020 ◽  
Vol 11 (4) ◽  
pp. 995-1012
Author(s):  
Lukas Brunner ◽  
Angeline G. Pendergrass ◽  
Flavio Lehner ◽  
Anna L. Merrifield ◽  
Ruth Lorenz ◽  
...  
Keyword(s):  
Climate Change ◽  
Retrospective Analysis ◽  
Climate Models ◽  
Cmip5 Models ◽  
Future Climate Change ◽  
Historical Period ◽  
Climate Change Scenarios ◽  
Uncertainty Range ◽  
Future Warming ◽  
The Mean

Abstract. The sixth Coupled Model Intercomparison Project (CMIP6) constitutes the latest update on expected future climate change based on a new generation of climate models. To extract reliable estimates of future warming and related uncertainties from these models, the spread in their projections is often translated into probabilistic estimates such as the mean and likely range. Here, we use a model weighting approach, which accounts for the models' historical performance based on several diagnostics as well as model interdependence within the CMIP6 ensemble, to calculate constrained distributions of global mean temperature change. We investigate the skill of our approach in a perfect model test, where we use previous-generation CMIP5 models as pseudo-observations in the historical period. The performance of the distribution weighted in the abovementioned manner with respect to matching the pseudo-observations in the future is then evaluated, and we find a mean increase in skill of about 17 % compared with the unweighted distribution. In addition, we show that our independence metric correctly clusters models known to be similar based on a CMIP6 “family tree”, which enables the application of a weighting based on the degree of inter-model dependence. We then apply the weighting approach, based on two observational estimates (the fifth generation of the European Centre for Medium-Range Weather Forecasts Retrospective Analysis – ERA5, and the Modern-Era Retrospective analysis for Research and Applications, version 2 – MERRA-2), to constrain CMIP6 projections under weak (SSP1-2.6) and strong (SSP5-8.5) climate change scenarios (SSP refers to the Shared Socioeconomic Pathways). Our results show a reduction in the projected mean warming for both scenarios because some CMIP6 models with high future warming receive systematically lower performance weights. The mean of end-of-century warming (2081–2100 relative to 1995–2014) for SSP5-8.5 with weighting is 3.7 ∘C, compared with 4.1 ∘C without weighting; the likely (66%) uncertainty range is 3.1 to 4.6 ∘C, which equates to a 13 % decrease in spread. For SSP1-2.6, the weighted end-of-century warming is 1 ∘C (0.7 to 1.4 ∘C), which results in a reduction of −0.1 ∘C in the mean and −24 % in the likely range compared with the unweighted case.

scholarly journals Primer registro del murciélago bigotón Pteronotus parnelli (Chiroptera: Mormoopidae) al Este de Sonora

2013 ◽  
Vol 3 (1) ◽  
pp. 11
Author(s):  
Martha V. Maldonado Bracamontes ◽  
Gerardo Carreón Arroyo ◽  
Isaias Ochoa Gutiérrez
Keyword(s):  
Protected Area ◽  
Ground Level ◽  
Breeding Population ◽  
East Central ◽  
Mustached Bat ◽  
Pteronotus Parnellii ◽  
Palabras Clave ◽  
Wilderness Area ◽  
The Town ◽  
Pteronotus Parnelli

AbstractParnell’s mustached bat, Pteronotus parnellii, is found from southern Sonora and Tamaulipas to Chiapas in Mexico. On October 3, 2012, at 18:30 hr, six and nine-meter nets were placed above water ponds in the Babisal creek located in the “Northern Jaguar Reserve” near the town of Sahuaripa. At 19:50 hrs the six-meter net was checked, and an adult male, without scrotum, of the species Pteronotus parnellii was found at a height of 70cm above ground level. The Sahuaripa region in east-central Sonora, is outside the known distribution range of this species extending it by at least 220 km north of the Sierra de Alamos. The “Northern Jaguar Reserve” where Pteronotus parnellii was found, is a protected area and an important wilderness area for the protection of the northernmost breeding population of jaguars. Key words: Pteronotus parnellii, Reserva Jaguar del Norte, Sonora, october. Palabras clave: Pteronotus parnellii, Reserva Jaguar del Norte, Sonora, octubre.

scholarly journals Observation of sensible and latent heat flux profiles with lidar

2020 ◽  
Vol 13 (6) ◽  
pp. 3221-3233 ◽  
Author(s):  
Andreas Behrendt ◽  
Volker Wulfmeyer ◽  
Christoph Senff ◽  
Shravan Kumar Muppa ◽  
Florian Späth ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Sensible Heat Flux ◽  
Ground Level ◽  
Sensible Heat ◽  
Flux Divergence ◽  
Convective Boundary ◽  
The Mean

Abstract. We present the first measurement of the sensible heat flux (H) profile in the convective boundary layer (CBL) derived from the covariance of collocated vertical-pointing temperature rotational Raman lidar and Doppler wind lidar measurements. The uncertainties of the H measurements due to instrumental noise and limited sampling are also derived and discussed. Simultaneous measurements of the latent heat flux profile (L) and other turbulent variables were obtained with the combination of water-vapor differential absorption lidar (WVDIAL) and Doppler lidar. The case study uses a measurement example from the HOPE (HD(CP)2 Observational Prototype Experiment) campaign, which took place in western Germany in 2013 and presents a cloud-free well-developed quasi-stationary CBL. The mean boundary layer height zi was at 1230 m above ground level. The results show – as expected – positive values of H in the middle of the CBL. A maximum of (182±32) W m−2, with the second number for the noise uncertainty, is found at 0.5 zi. At about 0.7 zi, H changes sign to negative values above. The entrainment flux was (-62±27) W m−2. The mean sensible heat flux divergence in the observed part of the CBL above 0.3 zi was −0.28 W m−3, which corresponds to a warming of 0.83 K h−1. The L profile shows a slight positive mean flux divergence of 0.12 W m−3 and an entrainment flux of (214±36) W m−2. The combination of H and L profiles in combination with variance and other turbulent parameters is very valuable for the evaluation of large-eddy simulation (LES) results and the further improvement and validation of turbulence parameterization schemes.

scholarly journals Boundary layer evolution over the central Himalayas from radio wind profiler and model simulations

2016 ◽  
Vol 16 (16) ◽  
pp. 10559-10572 ◽  
Author(s):  
Narendra Singh ◽  
Raman Solanki ◽  
Narendra Ojha ◽  
Ruud H. H. Janssen ◽  
Andrea Pozzer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Mixed Layer ◽  
Surface Ozone ◽  
Wrf Model ◽  
Ground Level ◽  
Wind Profiler ◽  
Pollution Transport ◽  
Local Boundary ◽  
The Mean

Abstract. We investigate the time evolution of the Local Boundary Layer (LBL) for the first time over a mountain ridge at Nainital (79.5° E, 29.4° N, 1958 m a.m.s.l.) in the central Himalayan region, using a radar wind profiler (RWP) during November 2011 to March 2012, as a part of the Ganges Valley Aerosol Experiment (GVAX). We restrict our analysis to clear–sunny days, resulting in a total of 78 days of observations. The standard criterion of the peak in the signal-to-noise ratio (S ∕ N) profile was found to be inadequate in the characterization of mixed layer (ML) top at this site. Therefore, we implemented a criterion of S ∕ N > 6 dB for the characterization of the ML and the resulting estimations are shown to be in agreement with radiosonde measurements over this site. The daytime average (05:00–10:00 UTC) observed boundary layer height ranges from 440 ± 197 m in November (late autumn) to 766 ± 317 m above ground level (a.g.l.) in March (early spring). The observations revealed a pronounced impact of mountain topography on the LBL dynamics during March, when strong winds (> 5.6 m s−1) lead to LBL heights of 650 m during nighttime. The measurements are further utilized to evaluate simulations from the Weather Research and Forecasting (WRF) model. WRF simulations captured the day-to-day variations up to an extent (r2 = 0.5), as well as the mean diurnal variations (within 1σ variability). The mean biases in the daytime average LBL height vary from −7 % (January) to +30 % (February) between model and observations, except during March (+76 %). Sensitivity simulations using a mixed layer model (MXL/MESSy) indicated that the springtime overestimation of LBL would lead to a minor uncertainty in simulated surface ozone concentrations. However, it would lead to a significant overestimation of the dilution of black carbon aerosols at this site. Our work fills a gap in observations of local boundary layer over this complex terrain in the Himalayas, and highlights the need for year-long simultaneous measurements of boundary layer dynamics and air quality to better understand the role of lower tropospheric dynamics in pollution transport.

scholarly journals Is the Responsiveness to Light Related to the Differences in Stem Straightness among Populations of Pinus pinaster?

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 383
Author(s):  
Rosario Sierra-de-Grado ◽  
Valentín Pando ◽  
Pablo Martínez-Zurimendi ◽  
Bruno Moulia
Keyword(s):  
Cross Sections ◽  
Pinus Pinaster ◽  
Radial Growth ◽  
Wood Quality ◽  
Secondary Growth ◽  
Natural Populations ◽  
Ecological Features ◽  
Stem Straightness ◽  
One Year ◽  
Stem Curvature

Stem straightness is related to wood quality and yield. Although important genetic differences in stem straightness among the natural populations of Pinus pinaster are well established, the main drivers of these differences are not well known. Since the responses of trees to light are key ecological features that induce stem curvature, we hypothesized that populations with better straightness should exhibit lower photomorphogenetic and phototropic sensitivity. We compared three populations to identify the main processes driven by primary and secondary growth that explain their differences in response to light. One-year-old seedlings were grown under two treatments—direct sunlight and lateral light plus shade—for a period of 5 months. The length and the leaning of the stems were measured weekly. The asymmetry of radial growth and compression wood (CW) formation were analyzed in cross-sections. We found differences among the populations in photomorphogenetic and phototropic reactions. However, the population with straighter stems was not characterized by reduced sensitivity to light. Photo(gravi)tropic responses driven by primary growth and gravitropic responses driven by secondary growth explained the kinetics of the stem leaning and CW pattern. Asymmetric radial growth and CW formation did not contribute to the phototropic reactions.

scholarly journals Thermal Diffusion of Isotopes in Pure Liquids

1966 ◽  
Vol 21 (9) ◽  
pp. 1348-1351
Author(s):  
A. Lodding
Keyword(s):  
Mass Flow ◽  
Liquid Metals ◽  
Density Fluctuations ◽  
Pure Liquid ◽  
Theoretical Treatment ◽  
Liquid Model ◽  
Order Of Magnitude ◽  
Mean Size ◽  
The Mean ◽  
Effective Cluster

A theoretical treatment is given of the recently discovered thermotransport effect in pure liquid metals. The isotope effect is related to the diffusive mass flow by a proportionality factor familiar from electrotransport. The mass flow is given primarily by the temperature dependence of the mean size or amount of density fluctuations in the liquid. Very little activation energy is required for diffusive motion, which takes place by cooperative position adjustments of neighbor atoms. The mean displacement length of the diffusing cluster is by an order of magnitude smaller than the effective cluster diameter. The liquid model suggested is coherent with models based on evidence from other experimental methods.

scholarly journals Mermin–Wagner fluctuations in 2D amorphous solids

2017 ◽  
Vol 114 (8) ◽  
pp. 1856-1861 ◽  
Author(s):  
Bernd Illing ◽  
Sebastian Fritschi ◽  
Herbert Kaiser ◽  
Christian L. Klix ◽  
Georg Maret ◽  
...  
Keyword(s):  
Computer Simulations ◽  
System Size ◽  
Amorphous Solids ◽  
Two Dimensions ◽  
Density Fluctuations ◽  
Long Wavelength ◽  
Broken Symmetries ◽  
Lindemann Criterion ◽  
The Mean ◽  
2D Crystals

In a recent commentary, J. M. Kosterlitz described how D. Thouless and he got motivated to investigate melting and suprafluidity in two dimensions [Kosterlitz JM (2016)J Phys Condens Matter28:481001]. It was due to the lack of broken translational symmetry in two dimensions—doubting the existence of 2D crystals—and the first computer simulations foretelling 2D crystals (at least in tiny systems). The lack of broken symmetries proposed by D. Mermin and H. Wagner is caused by long wavelength density fluctuations. Those fluctuations do not only have structural impact, but additionally a dynamical one: They cause the Lindemann criterion to fail in 2D in the sense that the mean squared displacement of atoms is not limited. Comparing experimental data from 3D and 2D amorphous solids with 2D crystals, we disentangle Mermin–Wagner fluctuations from glassy structural relaxations. Furthermore, we demonstrate with computer simulations the logarithmic increase of displacements with system size: Periodicity is not a requirement for Mermin–Wagner fluctuations, which conserve the homogeneity of space on long scales.

Within-tree patterns of wood stiffness for white spruce (Picea glauca) and trembling aspen (Populus tremuloides)

2014 ◽  
Vol 44 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Derek F. Sattler ◽  
Philip G. Comeau ◽  
Alexis Achim
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Radial Growth ◽  
Tree Height ◽  
White Spruce ◽  
Vertical Position ◽  
Trembling Aspen ◽  
Mixed Effect ◽  
Cambial Age ◽  
Rate Of Increase

Radial patterns of modulus of elasticity (MOE) were examined for white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuoides Michx.) from 19 mature, uneven-aged stands in the boreal mixedwood region of northern Alberta, Canada. The main objectives were to (1) evaluate the relationship between pith-to-bark changes in MOE and cambial age or distance from pith; (2) develop species-specific models to predict pith-to-bark changes in MOE; and (3) to test the influences of radial growth, relative vertical height, and tree slenderness (tree height/DBH) on MOE. For both species, cambial age was selected as the best explanatory variable with which to build pith-to-bark models of MOE. For white spruce and trembling aspen, the final nonlinear mixed-effect models indicated that an augmented rate of increase in MOE occurred with increasing vertical position within the tree. For white spruce trees, radial growth and slenderness were found to positively influence maximum estimated MOE. For trembling aspen, there was no apparent effect of vertical position or radial growth on maximum MOE. The results shed light on potential drivers of radial patterns of MOE and will be useful in guiding silvicultural prescriptions.

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