Atmosfera最新文献_第10页

Statistical analysis of the relationship between Quasi-Biennial Oscillation and Southern Annular Mode 准两年一次振荡与南环模关系的统计分析

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-12-09 DOI: 10.20937/atm.52910

F. C. Vasconcellos, M. Gava, C. Sansigolo

{"title":"Statistical analysis of the relationship between Quasi-Biennial Oscillation and Southern Annular Mode","authors":"F. C. Vasconcellos, M. Gava, C. Sansigolo","doi":"10.20937/atm.52910","DOIUrl":"https://doi.org/10.20937/atm.52910","url":null,"abstract":"The Southern Annular Mode (SAM) is an extratropical pattern that influences the climate of all Southern Hemisphere. However, the variability of this mode is an active area of research. The influence of lower frequency modes on SAM is a path to better knowledge about this pattern. The relationship between Quasi-Biennial Oscillation (QBO) and SAM’s counterpart in the Northern Hemisphere (Northern Annular Mode) has been addressed by previous work. Still, few studies focus on the association between QBO and SAM. The goal of this work was to evaluate the possible QBO-SAM relationship through statistical analyses. This association was investigated by comparing QBO and SAM indices, the latter on different levels of the troposphere and stratosphere, for the 1981-2010 period. The wavelet analysis showed that the SAM indices for troposphere and stratosphere presented variability in many scales, including a two-year band. Cross-wavelets techniques between QBO and SAM ratified that this relation has a complex interaction. There was a significant common high power around the two-year band, with lags varying over the analyzed period, including no lag. Further analysis without lag confirmed previous studies, indicating that the negative (positive) SAM phase is more frequent for easterly (westerly) QBO. However, this was not valid for all months. Some additional analysis suggested that the upward wave propagation to the stratosphere for each QBO phase changes the stratospheric jet and, consequently, the SAM phase.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41663654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A momentum-balance theory for the updraft structure in density currents analogous to squall lines 类似于飑线的密度流上升气流结构的动量平衡理论

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-12-09 DOI: 10.20937/atm.52899

Diego A. Alfaro, Fernando Lezana

引用次数: 1

Thermodynamic analysis of convective events that occurred in Belém-PA city 贝伦-PA市对流事件的热力学分析

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-12-09 DOI: 10.20937/atm.52934

L. M. Silva

{"title":"Thermodynamic analysis of convective events that occurred in Belém-PA city","authors":"L. M. Silva","doi":"10.20937/atm.52934","DOIUrl":"https://doi.org/10.20937/atm.52934","url":null,"abstract":"The Amazon Basin is dominated by convective rainfall with significant spatial and diurnal variability. Diurnal and seasonal distributions of convective events were determined from rainfall and Cloud Top Temperature (CTT) between January 2008 and December 2010 in city Belém-PA. The decis technique was used to select the most intense events (rainfall rate ≥ 15 mm h –1 ), which were subsequently, subclassified into deep convection events (DCE) and shallow convection events (SCE). Ninety four cases were found, mostly occurring between 12 and 19 LT, and 55% in the rainy season. Another set of DCE and SCE with rainfall rate ≥ 1 mm h –1 was selected to analyze the effect of seasonality. Of these, 42 cases were found also between 12 and 19 LT, with a maximum at 16 LT. Temperature profiles differed between the rainy and less rainy seasons, in the intensification of shallow and deep convection. Moisture profiles showed greater variability between 850 and 500 hPa, indicative of their role in convective activity; during the rainy season the atmosphere was more humid (less humid) before (at the time) of the occurrence of DCE. Wind components showed significant shear between surface and ~850 hPa, with stronger zonal component in the cases of DCE. The highest values of CAPE were observed about 2 to 3 hours before DCE and SCE, with maximum values before DCE in the rainy season. Results presented here are relevant to improve short-term forecasts and convective event simulations with numerical weather and climate models.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43254068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synoptic patterns of South Atlantic Convergence Zone episodes associated with heavy rainfall events in the city of Rio de Janeiro, Brazil 巴西里约热内卢市与强降雨事件相关的南大西洋辐合带事件的天气模式

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-12-09 DOI: 10.20937/atm.52942

G. Escobar, Ana Clara de Almeida Marques, C. Dereczynski

{"title":"Synoptic patterns of South Atlantic Convergence Zone episodes associated with heavy rainfall events in the city of Rio de Janeiro, Brazil","authors":"G. Escobar, Ana Clara de Almeida Marques, C. Dereczynski","doi":"10.20937/atm.52942","DOIUrl":"https://doi.org/10.20937/atm.52942","url":null,"abstract":"The present study provides a synoptic characterization of South Atlantic Convergence Zone (SACZ) episodes that caused heavy rainfall events (HRE) in the city of Rio de Janeiro (CRJ) between 2006 and 2016. A total of 77 SACZ episodes were identified in the CRJ (SCRJ), which represented 81% of the total SACZ events in Brazil. At least one day of HRE during the SACZ period (SHRE) was found in 37 SCRJ episodes, representing almost half (48%) of the SACZ events in the CRJ. In 68.6% of these cases, the heavy rainfall occurred on the first two days of the SHRE period. The mean synoptic pattern of SHRE showed a cold front in the Atlantic Ocean connected with a low-pressure system located near the coast of Rio de Janeiro state (RJ). The 850 hPa specific humidity showed a dipole pattern with positive anomalies in southeastern Brazil and negative anomalies in southern Brazil since the day before the occurrence of SHRE. An anomalous upper-level ridge in southeastern Brazil was relevant to intensifying the heavy rainfall in the CRJ. The synoptic classification showed four main surface synoptic patterns associated with SHRE. The two most frequent patterns were associated with a cold front close to the coast of RJ, and the other two were related to the presence of an anticyclone with blocking characteristics and to the presence of a weak extratropical cyclone near the coast of RJ.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42988106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

How COVID-19 induced lockdown impacts air quality in Delhi-NCR region of India? COVID-19引发的封锁如何影响印度德里- ncr地区的空气质量?

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-12-07 DOI: 10.20937/atm.52912

Jabrinder Singh

引用次数: 0

Respiratory Aerosols: the dominant route of the spread of COVID 19 呼吸道气溶胶:新冠病毒传播的主要途径

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-11-09 DOI: 10.20937/atm.52967

Rafael Nery Liñan Abanto

引用次数: 0

The UNAM-Droplet Freezing Assay: An Evaluation of the Ice Nucleating Capacity of the Sea-Surface Microlayer and Surface Mixed Layer in Tropical and Subpolar Waters unam液滴冻结试验:热带和亚极地水域海洋表面微层和表面混合层冰成核能力的评估

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-10-26 DOI: 10.20937/atm.52938

Luis A. Ladino, Javier Juárez-Pérez, Zyanya Ramírez-Díaz, L. Miller, Jorge Herrera, G. Raga, K. Simpson, Giuliana Cruz, Diana L. Pereira, Fernanda Córdoba

{"title":"The UNAM-Droplet Freezing Assay: An Evaluation of the Ice Nucleating Capacity of the Sea-Surface Microlayer and Surface Mixed Layer in Tropical and Subpolar Waters","authors":"Luis A. Ladino, Javier Juárez-Pérez, Zyanya Ramírez-Díaz, L. Miller, Jorge Herrera, G. Raga, K. Simpson, Giuliana Cruz, Diana L. Pereira, Fernanda Córdoba","doi":"10.20937/atm.52938","DOIUrl":"https://doi.org/10.20937/atm.52938","url":null,"abstract":"Ice nucleating particles (INPs) in the atmosphere are necessary to generate ice crystals in mixed-phase clouds, a crucial component for precipitation development. The sources and composition of INPs are varied: from mineral dust derived from continental erosion to bioaerosols resulting bubble bursting at the ocean surface. The performance of a home-built droplet freezing assay (DFA) device for quantificatying of the ice nucleating abilities of water samples via immersion freezing has been validated against both published results and analyses of samples from sea surface microlayer (SML) and bulk surface water (BSW) from the Gulf of Mexico (GoM) and Saanich Inlet, off Vancouver Island (VI), Canada. Even in the absence of phytoplankton blooms, all the samples contained ice nucleating particles at moderate concentrations, ranging from 6.0x10 1 to 1.1x10 5 L -1 water. The freezing temperatures (i.e., T 50 , the temperature at which 50% of the droplets freeze) of the samples decreased in order of VI SML > GoM BSW > GoM SML, indicating that the higher-latitude coastal waters have a greater potential to initiate cloud formation and precipitation.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"11 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84167335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Assessment of the accuracy of open-circuit respiration chambers for measuring enteric methane emissions in cattle 用于测量牛肠道甲烷排放的开路呼吸室的准确性评估

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-10-26 DOI: 10.20937/atm.52839

Jeyder Israael Arceo, Rafael Jiménez Ocampo, E. Flores-Santiago, C. S. Restrepo, Carlos Pérez, Francisco Javier Solorio Sánchez, P. Q. Owen, J. Ku-Vera

{"title":"Assessment of the accuracy of open-circuit respiration chambers for measuring enteric methane emissions in cattle","authors":"Jeyder Israael Arceo, Rafael Jiménez Ocampo, E. Flores-Santiago, C. S. Restrepo, Carlos Pérez, Francisco Javier Solorio Sánchez, P. Q. Owen, J. Ku-Vera","doi":"10.20937/atm.52839","DOIUrl":"https://doi.org/10.20937/atm.52839","url":null,"abstract":"Ruminants are the main source of methane emissions from the agricultural sector. Emission inventories and mitigation strategies require reliable technics of measurement. The respiration chamber methodology is a precise approach for measuring enteric methane emissions in cattle. A set of experiments was carried out to validate two respiration chambers for measuring enteric methane emissions of cattle. The chambers were calibrated considering three main components: the methane analyzer, the air duct and air extraction system, and the chamber itself, by evaluating linearity and response time of the analyzer, plateau variability and high purity methane recoveries in chambers. Recovery test calculations carried out after releasing high purity methane into the chambers gave calibration factors of 0.95 ± 0.05 and 1.03 ± 0.03 for the complete system of respirations chambers one and two, respectively, with corresponding uncertainties of 4.87 and 2.49%. Thus, the respiration chambers for enteric methane measurements of cattle at the University of Yucatan, Mexico function with precision and accuracy. This technique can be used to establish methane inventories and methane mitigation strategies in cattle.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47286120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A new index to assess meteorological drought: the Drought Exceedance Probability Index (DEPI) 气象干旱评价新指标——干旱超越概率指数(DEPI)

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-10-26 DOI: 10.20937/atm.52870

Natalia Limones, María Fernanda Pita López, J. Camarillo-Naranjo

引用次数: 1

The anomalous wet 2020 southeast Brazil austral summer: characterization and possible mechanisms 2020年巴西东南部南部夏季异常潮湿:特征和可能机制

IF 1.4 4区地球科学

Atmosfera Pub Date : 2020-10-26 DOI: 10.20937/atm.52919

F. C. Vasconcellos, Juan Neres de Souza

引用次数: 4