Nonlinear dynamics of meteorological variables: multifractality and chaotic invariants in daily records from Pastaza, Ecuador   总被引：1，自引：0，他引：1  

Humberto Millán  Aleksandar Kalauzi  Milena Cukic  Riccardo Biondi 《Theoretical and Applied Climatology》2010,102(1-2):75-85

Weather represents the daily state of the atmosphere. It is usually considered as a chaotic nonlinear dynamical system. The objectives of the present study were (1) to investigate multifractal meteorological trends and rhythms at the Amazonian area of Ecuador and (2) to estimate some nonlinear invariants for describing the meteorological dynamics. Six meteorological variables were considered in the study. Datasets were collected on a daily basis from January 1st 2001 to January 1st 2005 (1,460 observations). Based on a new multifractal method, we found interesting fractal rhythms and trends of antipersistence patterns (Fractal Dimension >1.5). Nonlinear time series analyses rendered Lyapunov exponent spectra containing more than one positive Lyapunov exponent in some cases. This sort of hyperchaotic structures could explain, to some extent, larger fractal dimension values as the Kaplan–Yorke dimension was also in most cases larger than two. The maximum prediction time ranged from ξ?=?1.69 days (approximately 41 h) for E/P ratio to ξ?=?14.71 days for evaporation. Nonlinear dynamics analyses could be combined with multifractal studies for describing the time evolution of meteorological variables.  相似文献   

Influence of olive mill waste application on the role of soil as a carbon source or sink     

R. Carbonell-Bojollo  R. Ordóñez-Fernández  A. Rodríguez-Lizana 《Climatic change》2010,102(3-4):625-640

Organic matter (OM) is involved in the enhancement of soil quality since it acts on soil structure, nutrient storage and biological activity. Organic carbon (OC), the dominant element constituent of OM, and related soil properties are probably the most widely acknowledged indicator of soil quality. The typically Mediterranean climate of the South of Spain promotes low yields on crops and low organic carbon in soil. The present work was carried out to evaluate the effect of the application of alperujo, olive oil waste difficult to eliminate, on the fixation or emission of carbon on soil in an olive grove situated in Montoro (Córdoba, Spain). In the study three treatments were considered: 15 kg (A), 7.5 kg (B), 0 kg (C) of alperujo per tree and the implementation of the amendment has been made for three consecutive years. The results confirm the benefits of the amendment on the carbon content organic soil with a fixation with respect to control of 4.8 and 6.1 t ha^???1 for the first year and 8.7 and 6.8 t ha^???1 for the second in treatments A and B, respectively. Of the different climatic agents considered in the study, it was the temperature which had a major influence on the emissions of CO₂ into the atmosphere and the flow of gas presented the highest values in soils treated with the highest dose.  相似文献   

Systematic Vertical Variation of Mesoscale Fluxes in the Nocturnal Boundary Layer     

Otávio C. Acevedo  Larry Mahrt 《Boundary-Layer Meteorology》2010,135(1):19-30

The vertical mesoscale flux in the nocturnal boundary layer is generally considered to be difficult to estimate because of the small mesoscale vertical velocities and the large random variation of the mesoscale fluxes. However, the mesoscale vertical flux of heat, computed from FLOSSII data, varies quasi-systematically with height, stability and time scale. Such systematic variation requires correction for sonic misalignment and averaging over a large quantity of data. The relation of the mesoscale heat flux to the vertical structure of the nocturnal boundary layer is examined. For the most common conditions, the vertical convergence of the mesoscale heat flux acts to reduce the nocturnal cooling rate. Important uncertainties are discussed as well as the need for improved observations.  相似文献   

The Ushnus in the astronomy of the Inca culture     

Milton Rojas Gamarra  Mônica Baptista Pereira Estrázulas  Steven R. Gullberg  César A. Zen Vasconcellos 《Astronomische Nachrichten》2024,345(2-3):e230181

Inferences are made about the relationship that existed between the Ushnus, pyramid-shaped, terraced structures used by the Incas in the most important ceremonies of the Tawantinsuyo, and Inka Astronomy. We draw attention to Ayni, Kawsaypacha, Duality, and Tinkuy principles, multidimensional codes of conduct and wisdom that are at the root of the Andean cosmovision and on their perception of the world and the Cosmos. These principles, examined as postulates, allow to elaborate axiomatic propositions to identify the Ushnus with ancient Astronomy practices. In a complementary statement, starting from a bi-conditional proposition, we may infer through reciprocal corollaries that the Inka earliest roots to a holistic learning and educational ambient in the Tawantinsuyo was not elitist, instead it was based on a epistemological construct that differs from the corresponding Western educational ambients. An epistemological and cognitive approach allows to identify an ancient elaborate process of knowledge construction, based on the four fundamental principles, corresponding to different levels of assimilation and comprehension. As a complementary aspect, we identify some of the most preserved Ushnus of the Inka “Empire.” Then we complement this contribution with a broader interpretation for the Ushnus.  相似文献   

Improvement of Vertical Diffusion Analytic Schemes Under Stable Atmospheric Conditions     

Amela Jeričević  Željko Večenaj 《Boundary-Layer Meteorology》2009,131(2):293-307

Based on gradient transport theory or K-theory, turbulent transport in the atmosphere has long been parameterized using the eddy diffusivity. Due to its simplicity, this approach has often been applied in many numerical models but rarely tested with observations. Here, the widely used O’Brien cubic polynomial approach has been validated together with an exponential approach against eddy diffusivity profiles determined from measurements and from large-eddy simulation data in stable conditions. Verification is completed by analyzing the variability effects on pollutant concentrations of two different vertical diffusion (K(z)) schemes incorporated in an atmospheric chemical model. It is shown that the analytical, exponential solution agrees better with observations than the O’Brien profile and should be used henceforth in practical applications.  相似文献   

Adaptation of Pressure Based CFD Solvers for Mesoscale Atmospheric Problems   总被引：1，自引：1，他引：0  

Gergely Kristóf  Norbert Rácz  Miklós Balogh 《Boundary-Layer Meteorology》2009,131(1):85-103

General purpose Computational Fluid Dynamics (CFD) solvers are frequently used in small-scale urban pollution dispersion simulations without a large extent of ver- tical flow. Vertical flow, however, plays an important role in the formation of local breezes, such as urban heat island induced breezes that have great significance in the ventilation of large cities. The effects of atmospheric stratification, anelasticity and Coriolis force must be taken into account in such simulations. We introduce a general method for adapting pressure based CFD solvers to atmospheric flow simulations in order to take advantage of their high flexibility in geometrical modelling and meshing. Compressibility and thermal stratification effects are taken into account by utilizing a novel system of transformations of the field variables and by adding consequential source terms to the model equations of incompressible flow. Phenomena involving mesoscale to microscale coupled effects can be analyzed without model nesting, applying only local grid refinement of an arbitrary level. Elements of the method are validated against an analytical solution, results of a reference calculation, and a laboratory scale urban heat island circulation experiment. The new approach can be applied with benefits to several areas of application. Inclusion of the moisture transport phenomena and the surface energy balance are important further steps towards the practical application of the method.  相似文献   

Spatial and temporal changes in dry-snow line altitude on the Antarctic Peninsula     

Jorge Arigony-Neto  Helmut Saurer  Jefferson C. Simões  Frank Rau  Ricardo Jaña  Steffen Vogt  Hermann Gossmann 《Climatic change》2009,94(1-2):19-33

Drastic changes were detected in glacial systems of the Antarctic Peninsula in the last decades. The observed phenomena comprise the disintegration of ice shelves, acceleration and thinning of glaciers, and retreat of glacier fronts. However, due to the lack of consistent systematic observations in particular of the higher parts of the glacial systems, it is difficult to predict further responses of the Antarctic Peninsula glaciers to climatic change. The present paper analyses spatial and temporal variations of changes in the dry-snow line altitude on the Antarctic Peninsula as extracted from a time series (1992–2005) of ERS-1/2 SAR and Envisat ASAR data. Upward changes in dry-snow line altitude were observed in general, and are attributed to extreme high-temperature events impacting the central plateaus of the Antarctic Peninsula and the increasing duration of warming periods. A mean decrease in dry-snow line altitude was detected on the west side of the peninsula and is identified as a response to recorded increase in precipitation and accumulation. These results validate the capability of SAR data for deriving superficial parameters of glaciers to be used as indicators of climatic changes in high-latitude regions where operational restrictions limit conventional meteorological observations.  相似文献   

Spatial trends in heavy metals and nitrogen deposition in Navarra (Northern Spain) based on moss analysis     

L. González-Miqueo  D. Elustondo  E. Lasheras  R. Bermejo  J. M. Santamaría 《Journal of Atmospheric Chemistry》2009,62(1):59-72

A biomonitoring survey using the moss species Hypnum cupressiforme Hedw. was performed in the North of Navarra (Spain) in 2006. The levels of V, Cr, Mn, Ni, Cu, Zn, As, Zr, Cd, Hg and Pb, and the total nitrogen content were determined in the samples by means of ICP-MS, CV-AA, and the Kjeldahl method. PCA analysis showed a differentiation between lithogenic (V, Cr, Mn, Ni, As and Zr) and anthropogenic elements (Mn, Cu, Zn, Cd, Hg and Pb). Spatial distribution maps were drawn using the kriging method, in order to identify the most affected areas and the main pollution sources. A similar spatial distribution was observed for the elements belonging to each group separated by the PCA, showing an important contribution from metal industries located in the Basque Country, as well as influence of long-range transboundary pollution processes. Background levels were also determined for the study area, along with the contamination factor for the different elements analysed. Mosses seemed to be good biomonitors of N deposition in areas of accumulation.  相似文献   

Effect of growth on active biomonitoring with terrestrial mosses     

J. Angel Fernández  Angela Ares  Ana Rey-Asensio  Alejo Carballeira  Jesus R. Aboal 《Journal of Atmospheric Chemistry》2009,63(1):1-11

The effects of growth of autoirrigated, shaded transplants of Pseudoscleropodium purum on the quantification of tissue concentrations of Cd, Cu, Hg, V and Zn, were investigated in 4 exposure periods, each of 56 days, at 7 sampling sites (contaminated and uncontaminated). Concentrations of the elements in the basal portions of the moss shoots were compared with the concentrations in the portions of the shoots that grew during the exposure period. Mercury and V were present at lower concentrations in the new portions of the shoots than in the basal portions, whereas the opposite was true for Cd, Cu and Zn. The magnitude of error introduced by growth was not negligible, and in some cases was higher than 40%, relative to the results obtained by analysis of the whole shoot. Devitalization of moss prior to its use as transplant material is recommended to avoid growth of the plant during the exposure period.  相似文献   

Classification of BeppoSAX’s gamma-ray bursts     

István Horváth 《Astrophysics and Space Science》2009,323(1):83-86

The BeppoSAX Catalog has been very recently published. In this paper we analyze—using the Maximum Likelihood (ML) method—the duration distribution of the 1003 GRBs listed in the catalog with duration. The ML method can identify the long and the intermediate duration groups. The short population of the bursts is identified only at a 96% significance level. MC simulation has been also applied and gives a similar significance level; 95%. However, the existence of the short bursts is not a scientific question after the Compton Gamma-Ray Observatory’s observation. Our minor result is this well-known fact that in the BeppoSAX data the short bursts are under-represented, mainly caused by the different triggering system. Our major result is the identification of the intermediate group in the BeppoSAX data. Therefore, four different satellites (CGRO, Swift, RHESSI and BeppoSAX) observed the intermediate type Gamma-Ray Burst.  相似文献