Analysis Of Vertical Structure Research Articles

Spatiotemporal Analysis of Southeast Asian Lower Atmosphere using Historical Radiosonde Data

This study utilized historical radiosonde data from 37 selected WMO stations to analyze the physical properties of Southeast Asian lower atmosphere in both spatial and temporal regimes. The proposed analysis method includes the estimation of static atmospheric parameters and their correlations, the trend analysis from the parameters’ time series, and the extraction of annual and interannual variations from the detrended parameters’ time series. The vertical structure analysis of temperature and pressure “profiles” (i.e., temperature and pressure as functions of altitude at a given time) shows that their residuals from the isentropic atmosphere are altitude-dependent and predictable. The correlation analysis between estimated parameters shows that the heat capacity ratio is a function of the environmental lapse rate, which can be used in the parameterization of the atmospheric model. The molar mass of the Southeast Asian lower atmosphere was also estimated from the parameterization to be 29.65 g/mol, slightly higher than that of the average value of dry air at 28.97 g/mol. The spatial analysis of their average values indicates that the Southeast Asian lower atmosphere can be zonally classified into the Northern Equatorial Subregion (NES) and Central Equatorial Subregion (CES), where their boundary is located between the latitude of 5° N to 10° N. The trend analysis of each parameter’s time series suggests that the Southeast Asian lower atmosphere is a transient system manipulated by climate oscillations and climate change. Their equilibrium values can be estimated using linear regression analysis. The results from the Lomb-Scargle periodogram analysis also suggest that the annual variation originated from the Brewer-Dobson Circulation (BDC) and the interannual variation was manipulated by climate oscillations such as the Quasi-biennial Oscillation (QBO). This knowledge can be used to adjust the isentropic model to suit applications requiring accurate approximation, parameterize the model without sacrificing accuracy, and study the effect of climate oscillations and climate change on the Southeast Asian lower atmosphere. HIGHLIGHTS Time series of Southeast Asian lower atmosphere’s physical parameters were estimated from historical radiosonde data Southeast Asian lower atmosphere can be classified into Northern and Central Equatorial Subregions based on physical parameters Southeast Asian lower atmosphere is a transient system manipulated by climate oscillations and climate change GRAPHICAL ABSTRACT

Layered Stochastic Approximation Monte-Carlo method for tall building and tower fragility in mixed wind load climates

Performance-based wind engineering has emerged as an active research field due to potential applications into design standards [e.g., by the American Society of Civil Engineers (ASCE) in the United States of America]. Therefore, novel and accurate methodologies are necessary to successfully implement practice-oriented guidelines. This study will systematically examine the use of the Layered Stochastic-Approximation Monte-Carlo method, recently explored to assess of wind-induced structural dynamic analysis of vertical structures. The study will utilize a standard tall building and a monopole tower structure to investigate maximum response in terms of lateral displacement and acceleration, and the behavior of a structural member in terms of demand-to-capacity index. Both serviceability and ultimate limit states will be considered. The proposed method will be verified against standard Monte-Carlo sampling to assess its adequacy, accuracy and potential limitations. Particular consideration will be devoted to the study of wind loads and response in mixed wind climates, characterized by the presence of both tropical cyclones (hurricanes) and extra-tropical depressions.

Global aerosol vertical structure analysis by clustering gridded CALIOP aerosol profiles with fuzzy k-means

Aerosol vertical structures are critical to understanding distribution and source-sink patterns of aerosol on a large scale. In this study, we carried out spatial clustering analysis for 10-years long CALIOP aerosol profiles with a fuzzy k-means (FKM) method. Raw and normalized data sets were both classified into three representative clusters. Raw aerosol profiles of original data described both aerosol density and structure patterns, which were classified into polluted cluster, medium cluster and clean cluster with visual inspection. The mean aerosol extinction coefficient values in near surface from large to small respectively belonged to polluted cluster, medium cluster and clean cluster. As altitude increased, mean aerosol extinction coefficients of polluted cluster were in rapid decline trend from surface to upper atmosphere. In comparison, there was a slower decrease speed for the aerosol extinction coefficient values of mean aerosol profiles of the other two clusters. Aerosol profiles clusters using normalized data could be used to describe aerosol vertical structure patterns. Normalized aerosol profiles were classified into boundary-layer concentrated cluster (boundary cluster), vertically even distributed cluster (v-even cluster) and surface-layer concentrated cluster (surface cluster). The boundary cluster was stable in the low atmosphere with a decline trend upwards, which was spatially corresponds to strong anthropogenic emission and dust regions. The mean normalized extinction coefficient values of v-even cluster were relatively stable in a large vertical range (about 4 km) at regions with relatively weak wind fields. The coefficients of surface cluster were mainly distributed in the near surface with mostly in coastlines and low aerosol optical depth (AOD) regions. The cluster analysis of CALIOP aerosol profiles provided general patterns for global distributions of aerosol profile density and structure.

Computationally efficient stochastic approach for the fragility analysis of vertical structures subjected to thunderstorm downburst winds

Thunderstorm downburst winds introduce considerable uncertainty in dynamical structural analysis because of wind load non-stationarity, which cannot be adequately modelled by conventional stationary wind simulations. Performance-based structural analysis in wind engineering practice, which considers uncertainty related to both error propagation and modeling simplifications, requires sampling the structural information from a large number of dynamic simulations. This task may be computationally intensive using traditional numerical integration techniques. This study examines the feasibility and advantages of utilizing a wavelet-Galerkin (WG) approach to numerically integrate the coupled stochastic dynamic equations of motion for tall building structures affected by thunderstorm wind loads. The study examines the stochastic maximum structural response at key locations. Fragility analysis is subsequently conducted using curves modelled with log-normal complementary cumulative distribution functions and surfaces modelled using logistic regression. Both a “point-like” (plate) structure and a benchmark tall building are used for verification of the proposed simulation approach.

Floristic, structural, and allometric equations to estimate arboreal volume and biomass in a cerradão site

This objective of this study was to characterize the floristic, structural, and ecological groups and to estimate the arboreal volume and biomass of a cerradão site in Palmas, Tocantins, Brazil. A forest inventory was conducted on 10.15 ha of the study area. Plots of 400-m2 were used for systematic sampling. All standing trees (dead or alive) with a breast-height diameter (DHB) greater than 5 cm were identified and measured. Floristic diversity and horizontal structure were assessed using the Shannon and importance value indices, respectively. Forest vertical structure was classified into three stratata and the tree species were categorized into ecological groups. Ninety tree volumes were rigorously cubed and weighed. Fresh- and dry biomass were sampled and estimated. Mathematical models were applied and adjusted to estimate tree volume and biomass. It was observed that the species Myrcia splendens and Emmotum nitens and the families Fabaceae and Chrysobalanaceae were dominant in our study site. The pioneer (613 individuals ha-1) and climax (530 individuals ha-1) tree species group predominated. The floristic diversity index was estimated as 3.35 nats ind- 1. The vertical structure analysis indicated fewer individuals in the superior stratum (13%) compared to the medium (63%) and inferior (24%) stratum. The Schumacher and Hall model showed better results with regard to estimated forest production. Forest volume and biomass estimates were 126.71 m³ ha-1 and 61.67 Mg ha-1, respectively. The studied cerradão area had high floristic diversity and climax species predominated. Since this cerradão is in close proximity to the Amazon biome, its volume and biomass stocks were higher than those estimated for other cerradão and forest formations within the Cerrado biome.

Cross‐shelf water exchange in the East China Sea as estimated by satellite altimetry and in situ hydrographic measurement

AbstractCombining satellite altimetry and in situ hydrographic measurement, we estimated the cross‐shelf transport (CST) and its spatial and temporal variations across 200 m isobath in the East China Sea (ECS) from 1993 to 2014. The vertically integrated CST can be dynamically divided into three parts: surface Ekman transport, geostrophic transport, and bottom Ekman transport. The results show that the 22 year‐mean, sectionally integrated CST to be 1.7 ± 2.0 Sv (positive in the on‐shelf direction), comprised of bottom and surface Ekman transports of 2.7 ± 1.0 Sv and 0.6 ± 0.6 Sv, respectively, that are partially offset by a geostrophic transport of −1.5 ± 1.7 Sv. The sectionally integrated CST shows significantly high power at roughly annual period from 1999 to 2001, with lower power at intra‐annual period. The vertically integrated CST to the northeast of Taiwan is the main source of sectionally integrated CST. The vertically integrated CST also shows significant variations in the 6–15 month period band to the northeast of Taiwan as well. The temporal variations of the sectionally integrated and vertically integrated CST are both controlled primarily by geostrophic transport and modulated by bottom Ekman transport. In the upper 50 m, the geostrophic current to the northeast of Taiwan exhibits large mean and significant variability. The empirical orthogonal function analysis of vertical structure of geostrophic current shows two significant modes with strong annual signal. The first mode is associated with the migration of Kuroshio axis near Taiwan, while the second mode is associated with the variation of the meander of the Kuroshio to the northeast of Taiwan.

FLORISTIC-STRUCTURAL CHARACTERIZATION AND SUCCESSIONAL GROUP OF TREE SPECIES IN THE CERRADO BIOME OF TOCANTINS STATE, BRAZIL

ABSTRACT: The objective of this study was to characterize the floristic composition, vegetation structure and ecological group of tree species in a cerradão forest (Cerrado biome) of Palmas, Tocantins State, Brazil. A forest inventory was performed in an area of 10.15 hectares, using systematic sampling with plots of 400 m², in which all standing trees, alive and dead, that had diameter at breast height (DBH) ≥ 5 cm were sampled and identified. A linear plateau regression model (LPR) was used for sample sufficiency analysis. The Shannon index (H') was used for assess the floristic diversity, and the Importance Value Index (IVI) for assess the horizontal structure. The forest was classified in three strata according to vertical structure analysis. The LPR showed that the sampling size was adequate. The predominate species in the area were Myrcia splendens, Emmotum nitens and Qualea parviflora, and species from the families Fabaceae and Chrysobalanaceae. The pioneer (613 individuals ha-1) and climax (530 individuals ha-1) species were the predominating groups. Regarding the richness index, the number of climax (57 species) and pioneer (25 species) species stood out. The alpha floristic diversity was 3.35 nats individuals-1 and the Pielou equability value J = 0.76. The diametric distribution showed a negative and balanced exponential pattern. Regarding the vertical stratification, the smallest amount of individuals was in the upper stratum (13%) and the highest in the mid stratum (63%) and in the lower stratum (24%). The use of floristic composition tools with horizontal and vertical structure analysis was effective for understand the tree community, which may be considered structured and diverse, thus able to restructure possible disturbances when preserved.

Generation of waves by jet-stream instabilities in winter polar stratosphere/mesosphere

In the paper we investigate the manifestation of large-scale and middle-scale atmospheric irregularities observed on stratosphere/mesosphere heights. We consider typical patterns of circulation in stratosphere and lower mesosphere which are formed due to a difference of air potential energy between equatorial and polar latitudes, especially in polar night conditions. On the base of ECMWF Era Interim reanalysis data we consider the dynamics of midlatitude winter jet-streams which transfer heat from low latitudes to polar region and which develop due to equator/pole baroclinic instabilities. We consider typical patterns of general circulation in stratosphere/lower mesosphere and reasons for creation of flaky structure of polar stratosphere. Also we analyze conditions that are favorable for splitting of winter circumpolar vortex during sudden stratosphere warming events and role of phase difference tides in this process. The analysis of vertical structure of the stratosphere wind shows the presence of regions with significant shear of horizontal velocity which favors for inducing of shear-layer instability that appears as gravity wave on boundary surface. During powerful sudden stratosphere warming events the main jet-stream can amplify these gravity waves to very high amplitudes that causes wave overturning and releasing of wave energy into the heat due to the cascade breakdown and turbulence. For the dynamics observed in reanalysis data we consider physical mechanisms responsible for observed phenomena.

Dynamic and Thermodynamic Predictors of Vertical Structure in Radar-Observed Regional Precipitation

Abstract Radar-observed vertical structure of precipitation as defined by contoured frequency by altitude diagrams (CFADs) is related to dynamic and thermodynamic environmental parameters. CFADs from 559 storms occurring over the years 2004–11 in the vicinity of Locarno, Switzerland, combined with Interim ECMWF Re-Analysis (ERA-Interim) data show that the radar-observed vertical structure of precipitation correlates with synoptic pattern (as defined by 1000- and 500-hPa geopotential heights), integrated water vapor flux, atmospheric stability, and vertical profiles of temperature, moisture, and wind. Following the analysis of vertical structure and environmental parameters, a generalized linear model (GLM) is developed for radar-observed vertical structure as a function of data from ERA-Interim. The GLM provides expected values for the vertical extent and magnitude of radar reflectivity and predicts storm vertical structure type with 79% overall accuracy. The relationships found between environmental parameters and storm vertical structure underscore the importance of including both dynamic and thermodynamic variables when evaluating climate change effects on precipitation. In addition, the ability of the GLM to reproduce storm types shows the potential for using GLMs as a link between lower-resolution global model data and high-resolution precipitation observations.

Estimation of eddy heat transport in the global ocean from Argo data

The Argo data are used to calculate eddy (turbulence) heat transport(EHT) in the global ocean and analyze its horizontal distribution and vertical structure. We calculate the EHT by averaging all the v0, T0profiles within each 2 � �2 � bin. The velocity and temperature anomalies are obtained by removing their climatological values from the Argo “instantaneous” values respectively. Through the Student’s t-test and an error evaluation, we obtained a total of 87% Argo bins with significant depth-integrated EHTs (D-EHTs). The results reveal a positive-and-negative alternating D-EHT pattern along the western boundary currents (WBC) and Antarctic Circumpolar Current (ACC). The zonally-integrated D-EHT (ZI-EHT) of the global ocean reaches 0.12 PW in the northern WBC band and –0.38 PW in the ACC band respectively. The strong ZI-EHT across the ACC in the global ocean is mainly caused by the southern Indian Ocean. The ZI-EHT in the above two bands accounts for a large portion of the total oceanic heat transport, which may play an important role in regulating the climate. The analysis of vertical structures of the EHT along the 35 � N and 45 � S section reveals that the oscillating EHT pattern can reach deep in the northern WBC regions and the Agulhas Return Current (ARC) region. It also shows that the strong EHT could reach 600 m in the WBC regions and 1 000 m in the ARC region, with the maximum mainly located between 100 and 400 m depth. The results would provide useful information for improving the parameterization scheme in models.

Characterization of photochemical pollution at different elevations in mountainous areas in Hong Kong

Abstract. To advance our understanding on the factors that affect photochemical pollution at different elevations in mountainous areas, concurrent systematic field measurements (September to November 2010) were conducted at a mountain site and at an urban site at the foot of the mountain in Hong Kong. The mixing ratios of air pollutants were greater at the foot of the mountain (i.e., Tsuen Wan urban site, TW) than near the summit (i.e., Tai Mao Shan mountain site, TMS), expect for ozone. In total, only one O3 episode day was observed at TW, whereas twenty-one (21) O3 episode days were observed at TMS. The discrepancy of O3 at the two sites was attributed to the mixed effects of NO titration, vertical meteorological conditions, regional transport and mesoscale circulations. The lower NO levels at TMS and the smaller differences of "oxidant" Ox (O3 + NO2) between the two sites suggested that variations of O3 at the two sites were partly attributed to different degree of NO titration. In addition, analysis of vertical structure of meteorological variables revealed that the inversion layer at the range of altitudes of 500–1000 m might be another factor that caused the high O3 levels at TMS. Furthermore, analyses of the wind fields, the levels of air pollutants in different air flows, ratios of different trace gases and the correlation between variability and the lifetime of VOCs (volatile organic compounds) indicated that high O3 concentrations at TMS were somewhat influenced by regional air masses from the highly polluted Pearl River delta (PRD) region. In particular, the diurnal profiles and correlations of gaseous pollutants suggested influence of mesoscale circulations, which is confirmed using the Master Chemical Mechanism moving box model (Mbox) and the Weather Research and Forecasting (WRF) model. By investigating the correlations of observed O3 and NOx* and the relationships of O3 and its precursors by an observation-based model (OBM), as well as the ratios of VOC/NOx, it was concluded that photochemical O3 formation at TMS was mostly influenced by VOCs, with measurable impact of NOx, while O3 production at TW was generally limited by the concentrations of VOCs. This is the first report of the comprehensive analysis on the data of photochemical pollution obtained from concurrent measurements in mountainous areas in the PRD region.

Capabilities: Structure, Agency, and Evolution

This paper examines conceptual issues and reviews empirical results bearing on the relationship between research approaches emphasizing organizational capabilities and those based in transaction cost economics (TCE)—or in organizational economics more generally. Following a review of conceptual fundamentals—what capability is and why organizations differ in capability—it assesses recent progress toward an integration of the capabilities and transaction cost approaches, primarily in the context of the analysis of vertical structure and related phenomena. This review suggests that progress has been substantial and that the key elements of a promising dynamic synthesis have been identified. The paper then considers issues that call for attention if further progress is to be achieved. The first of these is the role of agency, which must be seen in expansive terms (relative to standard economic rationality) if its evolutionary significance is to be fully appreciated. The second is the role of structure, or more specifically, industry architecture, which affects capability development by way of its effect on the feedback that firms receive. After drawing on the recent financial crisis for an illustration of these ideas, this paper considers the rise of interest in business models as a useful field of application, and it concludes with a discussion of the role of organizational economics (beyond TCE). We argue that, whatever the theoretical perspective at the level of the firm, analyses must reach beyond that level to grasp the important causal forces affecting capability development, firm boundaries, and structural features more generally.

Near-Real-Time Applications of CloudSat Data

Abstract Within 2 months of its launch in April 2006 as part of the Earth Observing System A-Train satellite constellation, the National Aeronautics and Space Administration Earth System Science Pathfinder (ESSP) CloudSat mission began making significant contributions toward broadening the understanding of detailed cloud vertical structures around the earth. Realizing the potential benefit of CloudSat to both the research objectives and operational requirements of the U.S. Navy, the Naval Research Laboratory coordinated early on with the CloudSat Data Processing Center to receive and process first-look 94-GHz Cloud Profiling Radar datasets in near–real time (4–8 h latency), thereby making the observations more relevant to the operational community. Applications leveraging these unique data, described herein, include 1) analysis/validation of cloud structure and properties derived from conventional passive radiometers, 2) tropical cyclone vertical structure analysis, 3) support of research field programs, 4) validation of numerical weather prediction model cloud fields, and 5) quantitative precipitation estimation in light rainfall regimes.

On the combined use of satellite multispectral and radar polarimetric measurements to infer cloud microphysics

The extensive availability of multispectral satellite observations and polarimetric ground radar measurements enhances the remote sensing capabilities in studying structure and dynamics of cloud systems at all relevant scales. We present here a combined approach to perform a detailed cloud vertical structure analysis, by means of MODIS VIS-NIR products and C-band polarimetric radar data. Satellite products include estimates of cloud optical thickness, cloud particles effective radius and cloud top phase, to be matched with the polarimetric hydrometeor 3D classification as obtained by a fuzzy logic algorithm. The problem of matching of the two datasets is discussed and the procedure is applied to three case studies that occurred in Northern Italy. Results are presented in terms of vertical hydrometeor profile and satellite derived microphysical cloud properties, showing the capability of the combined approach in the 3D rendering of cloud structures, with envisaged applications for precipitation studies and data assimilation in meteorological models.

Water Vapor Variability in the Tropical Western Pacific from 20-year Radiosonde Data

The 20-year (1976–1995) daily radiosonde data at 17 stations in the tropical western Pacific was analyzed. The analysis shows that the atmosphere is more humid in a warmer climate on seasonal, inter-annual and long-term (20-year) time scales, implying a positive water vapor feedback. The vertical structure of the long-term trends in relative humidity (RH) is distinct from that on short-term (seasonal and inter-annual) time scales, suggesting that observed water vapor changes on short time scales could not be considered as a surrogate of long-term climate change. The increasing trend of RH (3%–5% / decade) in the upper troposphere is stronger than that in the lower troposphere (1%2%–2% / decade). Such vertical structure would amplify positive water vapor feedback in comparison to the common assumption of constant RH changes vertically. The empirical orthogonal function (EOF) analysis of vertical structure of RH variations shows distinct features of the vertical structure of the first three EOFs. The first three EOFs are optimal for representation of water vapor profiles and provide some hints on physical mechanisms responsible for observed humidity variability. Vaisala radiosondes were used at nine stations, and VIZ radiosondes used at other eight stations. The Vaisala data are corrected for temperature-dependence error using the correction scheme developed by NCAR I A TD and Vaisala. The comparison of Vaisala and VIZ data shows that the VIZ-measured RHs after October 1993 have a moist bias of ~ 10% at RHs < 20%. During 1976–1995, several changes including both instruments and reporting practice have been made at Vaisala stations and introduce errors to long-term RH variations.

気象衛星「ひまわり」直接受信システムの農業気象への応用に関する研究(第3報) : Photoshopによる受信雲画像の鉛直構造解析

気象衛星「ひまわり」直接受信システムの農業気象への応用に関する研究(第3報) : Photoshopによる受信雲画像の鉛直構造解析