scholarly journals Easterly Wave Disturbances over Northeast Brazil: An Observational Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Helber Barros Gomes ◽  
Tércio Ambrizzi ◽  
Dirceu Luís Herdies ◽  
Kevin Hodges ◽  
Bruce Francisco Pontes da Silva

This paper aims to identify the circulation associated with Easterly Wave Disturbances (EWDs) that propagate toward the Eastern Northeast Brazil (ENEB) and their impact on the rainfall over ENEB during 2006 and 2007 rainy seasons (April–July). The EWDs identification and trajectory are analyzed using an automatic tracking technique (TracKH). The EWDs circulation patterns and their main features were obtained using the composite technique. To evaluate the TracKH efficiency, a validation was done by comparing the EWDs number tracked against observed cases obtained from an observational analysis. The mean characteristics of EWDs are 5.5-day period, propagation speed of ~9.5 m·s−1, and a 4500 km wavelength. A synoptic analysis shows that between days −2 d and 0 d, the low level winds presented cyclonic relative vorticity and convergence anomalies both in 2006 and 2007. The EWDs signals are strongest at low levels. The EWDs propagation is associated with relative humidity and precipitation positive anomalies and OLR and omega negative anomalies. The EWDs tracks are seen over all ENEB and their lysis occurs between the ENEB and marginally inside the continent. The tracking captured 71% of EWDs in all periods, indicating that an objective analysis is a promising method for EWDs detection.

2011 ◽  
Vol 26 (2) ◽  
pp. 225-235 ◽  
Author(s):  
Roger Rodrigues Torres ◽  
Nelson Jesus Ferreira

Abstract This research aims to analyze two easterly wave disturbance events that reached the east coast of Northeast Brazil (NEB) on 15 May 2005 and 20 June 2006. The performance of the regional Eta Model was evaluated through four sets of experiments using different horizontal resolutions (10 and 40 km) and convective parameterization schemes [Betts–Miller–Janjić (BMJ) and Kain–Fritsch (KF)]. Through analysis of 700-hPa wind fields, all experiments, with 40- and 10-km horizontal resolutions and using the BMJ and KF schemes, were shown to well represent a trough propagating westward from about 20°W to NEB, with a 5-day forecast range. When evaluating the model sensitivity to different convective parameterizations, all the experiments showed similar results and underestimated rainfall in most of the domain. The obtained results suggest the need to extend this analysis to a larger number of cases and to test other cumulus parameterizations in order to improve the rainfall forecast in eastern NEB.


1982 ◽  
Vol 100 (2) ◽  
pp. 279-284 ◽  
Author(s):  
R. C. Arora ◽  
R. S. Pandey

Abstract. Domestic buffaloes were used to characterize the pattern of progesterone, oestradiol-17β, LH and androgen in the systemic circulation following infertile insemination. Concentrations of hormones were measured by RIA in blood samples collected daily or at alternate days following insemination. The concentration of progesterone was lowest on the day of insemination, and increased significantly to a peak level of 4.00 ± 0.60 ng/ml by day 13 post insemination. After day 17, it declined significantly (P < 0.01) to reach low levels by day 21. The concentration of oestradiol-17β was high at the time of insemination and declined significantly (P < 0.01) by day 2 after insemination. It was maintained around the basal level till day 18 with minor peaks in between this period. It again rose significantly (P < 0.01) at subsequent oestrus. The mean level of LH was highest at the time of insemination, and declined significantly (P < 0.01) by day 1 post insemination. It did not vary appreciably till the animal returned to oestrus. The oestrous value of LH and progesterone were negatively correlated (r = −0.77). The androgen level was observed to be high at insemination in 3 out of 5 animals, but the overall pattern of this steroid was inconsistent during the period studied. A high concentration of androgen was recorded in all the animals from day 2–5 before the onset of oestrus.


2007 ◽  
Vol 64 (3) ◽  
pp. 695-710 ◽  
Author(s):  
H. de Vries ◽  
J. D. Opsteegh

Abstract Optimal perturbations are constructed for a two-layer β-plane extension of the Eady model. The surface and interior dynamics is interpreted using the concept of potential vorticity building blocks (PVBs), which are zonally wavelike, vertically confined sheets of quasigeostrophic potential vorticity. The results are compared with the Charney model and with the two-layer Eady model without β. The authors focus particularly on the role of the different growth mechanisms in the optimal perturbation evolution. The optimal perturbations are constructed allowing only one PVB, three PVBs, and finally a discrete equivalent of a continuum of PVBs to be present initially. On the f plane only the PVB at the surface and at the tropopause can be amplified. In the presence of β, however, PVBs influence each other’s growth and propagation at all levels. Compared to the two-layer f-plane model, the inclusion of β slightly reduces the surface growth and propagation speed of all optimal perturbations. Responsible for the reduction are the interior PVBs, which are excited by the initial PVB after initialization. Their joint effect is almost as strong as the effect from the excited tropopause PVB, which is also negative at the surface. If the optimal perturbation is composed of more than one PVB, the Orr mechanism dominates the initial amplification in the entire troposphere. At low levels, the interaction between the surface PVB and the interior tropospheric PVBs (in particular those near the critical level) takes over after about half a day, whereas the interaction between the tropopause PVB and the interior PVBs is responsible for the main amplification in the upper troposphere. In all cases in which more than one PVB is used, the growing normal mode configuration is not reached at optimization time.


2013 ◽  
Vol 28 (5) ◽  
pp. 1241-1260 ◽  
Author(s):  
Clotilde Augros ◽  
Pierre Tabary ◽  
Adrien Anquez ◽  
Jean-Marc Moisselin ◽  
Pascal Brovelli ◽  
...  

Abstract An algorithm for the detection of horizontal wind shear at low levels was developed. The algorithm makes use of data collected by all radars from the Application Radar à la Météorologie Infra-Synoptique (ARAMIS) operational network, in order to build a complete mosaic of wind shear over metropolitan France. The product provides an estimation of the maximum horizontal wind shear detected in the low levels, between 0 and 2 km AGL. Examination of the wind shear mosaic for different cases shows that the product is able to retrieve small-scale wind shear signatures that can be linked to either convergence lines ahead of convective cells, which are indicative of gust fronts, or strong convergence areas inside intense cells. A statistical evaluation of the wind shear mosaic was performed, by comparing horizontal wind shear observed inside the area defined by convective objects with wind gusts recorded along their trajectory by weather stations. A link between those different observations was clearly established. Therefore, the use of wind shear for wind gust prediction was tested in combination with other parameters: an estimation of the energetic potential of density currents, the cell surface with reflectivity over 51 dBZ, relative helicity, and cell propagation speed. Different wind gust warning rules were tested on 468 convection nowcasting objects (CONOs). The results clearly highlighted the benefits of using wind shear for wind gust estimation, and also demonstrated the improvement in forecasting skill when combining different parameters. The wind shear mosaic will be produced operationally before the end of 2013 and will be used to improve wind gust warnings provided to end users.


2016 ◽  
Vol 29 (suppl 1) ◽  
pp. 27-30 ◽  
Author(s):  
Graziela Aparecida Nogueira de Almeida RIBEIRO ◽  
Helenice Brizolla GIAMPIETRO ◽  
Lídia Barbieri BELARMINO ◽  
Wilson SALGADO-JÚNIOR

Abstract Background: The psychologist who works in bariatric surgery has a role to receive, evaluate, prepare and educate the patient who will undergo the surgical procedure. Psychological evaluation becomes important in so far as allows us to obtain data on personal and familiar history and allow tracing of possible psychopathology. Aim: To collect data on psychological evaluations of patients in a bariatric surgery service of a public hospital in order to describe the psychological profile of patients in this service. Method: Data were collected from 827 patients between 2001 and 2015, using data from an interview, Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Binge Eating Scale (BES). Results: The mean age of patients before surgery was 39 years+/- 10, the mean BMI was 51 kg/m²+7, and most patients (81%) were female. The average score on the BDI was 14.8+8 and women had significantly higher scores than men. On the BAI the average score was 11+8 and on the ECAP was 14+8, both with no difference between groups. Conclusions: Psychosocial characteristics of the patients points to the significant presence of indicators of depression, with low levels of anxiety and binge eating.


2015 ◽  
Vol 45 (3) ◽  
pp. 613-629 ◽  
Author(s):  
M. Jeroen Molemaker ◽  
James C. McWilliams ◽  
William K. Dewar

AbstractThe California Undercurrent (CUC) flows poleward mostly along the continental slope. It develops a narrow strip of large negative vertical vorticity through the turbulent boundary layer and bottom stress. In several downstream locations, the current separates, aided by topographic curvature and flow inertia, in particular near Point Sur Ridge, south of Monterey Bay. When this happens the high-vorticity strip undergoes rapid instability that appears to be mesoscale in “eddy-resolving” simulations but is substantially submesoscale with a finer computational grid. The negative relative vorticity in the CUC is larger than the background rotation f, and Ertel potential vorticity is negative. This instigates ageostrophic centrifugal instability. The submesoscale turbulence is partly unbalanced, has elevated local dissipation and mixing, and leads to dilution of the extreme vorticity values. Farther downstream, the submesoscale activity abates, and the remaining eddy motions exhibit an upscale organization into the mesoscale, resulting in long-lived coherent anticyclones in the depth range of 100–500 m (previously called Cuddies) that move into the gyre interior in a generally southwestward direction. In addition to the energy and mixing effects of the postseparation instability, there is are significant local topographic form stress and bottom torque that retard the CUC and steer the mean current pathway.


2017 ◽  
Vol 27 (3) ◽  
pp. 251-256
Author(s):  
Summer Van Arsdale ◽  
Sarah E. Yost ◽  
Chiu-Hsieh Hsu ◽  
Mary Meer ◽  
Shari Schoentag ◽  
...  

Objective: Pyridoxine is 1 of 8 B vitamins that assist in a variety of essential functions including immune functions. The purpose of this study was to assess the risk factors associated with low pyridoxine levels in solid organ transplantation recipients. Design: The study cohort was divided into 2 groups: (a) patients with normal pyridoxine levels or (b) patients with low pyridoxine levels. Dietary evaluation and clinical characteristics of all patients, rejection episodes, and immunosuppression were collected. Simple descriptive statistics were used to analyze the overall cohort. Results: Of the 48 patients, 29 (60%) in the study cohort were identified to have low pyridoxine levels. The mean interval between transplantation and pyridoxine level check was 910 days (standard deviation [SD] 456). The mean weight at the time of dietary consultation was 80 kg (SD 20.7). More patients in the deficient group received thymoglobulin for rejection treatment (56% vs 0%; P = .01) and were thymoglobulin recipients (78% vs 10%; odds ratio [OR] = 31.5; 95% confidence interval [CI], 2.35-422.30; P < .01). A strong correlation was identified between thymoglobulin treatment for induction and a low level of pyridoxine (correlation coefficient R = 0.6, P = .004) and between thymoglobulin treatment for rejection and a low pyridoxine level (correlation coefficient R = 0.5, P = .05). Based on multivariate logistic regression analysis, only thymoglobulin treatment (induction or rejection treatment) was significantly associated with low pyridoxine levels (OR = 19.5, 95% CI, 1.01-375.24; P < .05). Conclusions: Low levels of pyridoxine appear to be relatively common, and thymoglobulin treatments are associated with low pyridoxine levels. Prospective studies are needed to confirm and valuate the significance of these findings.


2015 ◽  
Vol 68 (4) ◽  
pp. 367-372
Author(s):  
Irene Câmara Camacho ◽  
Rita Câmara ◽  
Roberto Camacho

<p>The pollinic spectrum of the Madeira region is dominated by grass pollen, which also represents an important aeroallergen in Europe. The present work aims to analyze the main features of the Poaceae pollen season in the Madeira region to determine the allergic risk. The study took place in Funchal city, the capital of Madeira Island, over a period of 10 years (2003–2012). The airborne pollen monitoring was carried out with a Hirst type volumetric trap, following well-established guidelines.</p><p>In the atmosphere of Funchal, the mean annual Poaceae pollen index was 229. The mean Poaceae pollen season lasts 275 days, with an onset date in January/March and an end date in November/December. Poaceae counts showed a seasonal variation with 2 distinct peaks: a higher peak between March and June, and the second one in autumn. The peak values occurred mainly between April and June, and the highest peak was 93 grains/m<sup>3</sup>, detected on the 27th May of 2010. The Poaceae pollen remaining at low levels during the whole growing season, presenting a nil to low allergenic risk during most of the study period. Higher critical levels of allergens have been revealed after 2006. In general, the pollen risk from Poaceae lasted only a few days per year, despite the very long pollen season and the abundance of grasses in the landscape of Madeira Island.</p>


2011 ◽  
Vol 11 (12) ◽  
pp. 33465-33509 ◽  
Author(s):  
J. P. Zhang ◽  
T. Zhu ◽  
Q. H. Zhang ◽  
C. C. Li ◽  
H. L. Shu ◽  
...  

Abstract. This study investigated the air pollution characteristics of synoptic-scale circulation in the Beijing megacity, and provided holistic evaluation of the impacts of circulation patterns on air quality during the 2008 Beijing Summer Olympics. Nine weather circulation types (CTs) were objectively identified over the North China region during 2000–2009, using obliquely rotated T-mode principal component analysis (PCA). The resulting CTs were examined in relation to the local meteorology, regional transport pathways, and air quality parameters, respectively. The FLEXPART-WRF model was used to calculate 48-h backward plume trajectories for each CT. Nine CTs were characterized, with distinct local meteorology and air mass origins. CT 1 (high to the west with a strong pressure gradient) was characterized by a northwestern origin, with the smallest local and southeasterly air mass sources, and CT 6 (high to the northwest) had air mass sources mostly from the north and east. In contrast, CTs 5, 8, and 9 (unique, high to the east, and low to the northwest, respectively) were characterized by southern and southeastern trajectories, which indicated a greater influence of high pollutant emission sources. In turn, poor air quality in Beijing (high loadings of PM10, BC, SO2, NO2, O3, AOD, and low visibility) was associated with these CTs. Good air quality in Beijing was associated with CTs 1 and 6. The average visibilities (with ±1 σ) in Beijing for CTs 1 and 6 during 2000–2009 were 18.5 ± 8.3 km and 14.3 ± 8.5 km, respectively. In contrast, poor visibility values of 6.0 ± 3.5 km, 6.6 ± 3.7 km, and 6.7 ± 3.6 km were found in CTs 5, 8, and 9, respectively. The mean concentrations of PM10 for CTs 1, 6, 5, 8, and 9 during 2005–2009 were 90.3 ± 76.3 μg m−3, 111.7 ± 89.6 μg m−3, 173.4 ± 105.8 μg m−3, 158.4 ± 90.0 μg m−3, and 151.2 ± 93.1 μg m−3, respectively. Analysis of the relationship between circulation pattern and air quality during the emission control period suggests that CTs are the primary drivers of day-to-day variations in pollutant concentrations over Beijing and its vicinity. During the Olympics period, the frequency of CT 6 was twice that of the mean in August from 2000 to 2009. This CT had northerly transport pathways and favorable meteorological conditions (e.g. frequent precipitation) for clean air during the Olympics. Assuming that relationships between CTs and air quality parameters in the same season (month) were constant in different years, the relative contributions of synoptic circulation to decreases in PM10, BC, SO2, NO2, CO, AOD, and horizontal light extinction during the Olympics were estimated as 19 ± 14%, 18 ± 13%, 41 ± 36%, 12 ± 7%, 19 ± 11%, 25 ± 28%, and 50 ± 46%, respectively.


1970 ◽  
Vol 63 (4) ◽  
pp. 705-716 ◽  
Author(s):  
U. Larsson-Cohn ◽  
E. D. B. Johansson ◽  
L. Wide ◽  
C. Gemzell

ABSTRACT Daily determinations of the plasma level of progesterone and the urinary excretion of luteinizing hormone (LH) and total oestrogens were performed in 6 subjects during one control cycle, immediately followed by three cycles of daily treatment with 0.5 mg of chlormadinone acetate continuously. The control cycles were ovulatory according to the parameters investigated. Two of the women showed a normal LH excretion pattern in all treatment cycles. The four other subjects also had periodical variations in the LH excretion but no distinct midcycle peaks occurred. The mean oestrogen excretion was increased in all three treatment cycles but the difference was satistically significant only in the last two cycles. Compared with the treatment cycles, the sum of progesterone values was significantly decreased in the first two cycles. Chlormadinone acetate in this dose had no thermogenic effect. Three of the subjects showed bleeding irregularities which had no clear connection with the hormone variations measured in the study. It is suggested that the low levels of progesterone might be due to a defective corpus luteum function.


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