Journal of Aerospace Technology and Management ISSN: 1984-9648 [email protected] Instituto de Aeronáutica e Espaço Brasil Souza Corrêa, Cleber Statistical Analysis of Spatial and Temporal Variability of Maximum Precipitation Events on the Rio Grande do Sul Journal of Aerospace Technology and Management, vol. 4, núm. 2, abril-agosto, 2012, pp. 227-235 Instituto de Aeronáutica e Espaço São Paulo, Brasil Available in: http://www.redalyc.org/articulo.oa?id=309426226005 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative GRLMDWP Statistical Analysis of Spatial and Temporal Variability of Maximum Precipitation Events on the Rio Grande do Sul Cleber Souza Corrêa* ,QVWLWXWRGH$HURQiXWLFDH(VSDoR6mR-RVpGRV&DPSRV63±%UD]LO Abstract: A statistical analysis of precipitation at Rio Grande do Sul State was presented in this article. The aim of this worN was to identify spatial and temporal patterns of maximum precipitation, which was achieved Ey ¿ttinJ a theoretical varioJram in maximum annual rainfalls and its times of occurrence. ,n the literature, it was found that this pattern occurs accordinJ to phenomena typical from middle latitude, such as low and hiJh level Met, and interactions Eetween them. Some years aJo, the relationship Eetween maximum annual rainfalls and synoptic predominant con¿Jurations was found. Therefore, this worN souJht on understandinJ the climatic characteristics that are important in Aerospace and Aeronautics, as extreme weather can cause numerous consequences in these activities. The use and validation of this proposed method would maNe possiEle its application in other reJions of interest in the %ra]ilian Aerospace. 8nderstandinJ these climatoloJical features of the atmospheric circulation dynamics, and analy]inJ maximum annual rainfall would allow a more ef¿cient and appropriate climate trend forecast and its application in aerospace activities. Keywords: Geostatistics, Maximum Annual Rainfall, Low Level Jet. INTRODUCTION In Rio Grande do Sul State, the formation of mesoscale States of America (Whiteman et al 7KHH[DPLQD- convective systems (MCS) may be associated with different tion of radiosonde data in cases with and without jet has a spatial and temporal scales, both in the planetary boundary GLIIHUHQWVSHFL¿FKXPLGLW\DYHUDJHRIDERXWJNJ7KH layer (PBL) and mesoscale, with a wide range of mechanisms transport performed of the LLJ overnight associated with responsible for its formation. PDJQLWXGHVRIWKHVSHFL¿FKXPLGLW\RIDERXWJNJFDQ Helfand and Schubert (1995) argue that low-level jets JHQHUDWHDYHU\LQWHQVHÀX[DQGVHYHUHSUHFLSLWDWLRQ&KHQ (LLJ) are the key processes in the transportation balance of et al. (1991) studied cyclones in the lee of the mountains moisture entering the mainland United States overnight. (shortwave) in East Asia, in the Eastern Tibetan Plateau, Higgins et al. (1997) featured a daily cycle of precipita- especially in the summer rainy season over Southeast China tion using hourly observations from 1963 to 1993, revealing and Taiwan area, from May to June. D ZHOOGH¿QHG PD[LPXP QLJKW RQ WKH *UHDW 3ODLQV LQ This period is characterized by severe rainfall and is spring and in summer. DFFRPSDQLHGE\WKHGHYHORSPHQWDQGLQWHQVL¿FDWLRQRI//- During the summer, there was 25% more precipitation 1RUWKZDUG LQ WKH ORZHU WURSRVSKHUH &KHQ DQG<X during the night than during the day. The impact of LLJ on analyzing data of precipitation during the rainy season on China the balance sheet total precipitation shows an increase of DQG-DSDQIRXQGFDVHVRIGDLO\UDLQIDOODURXQGPPSHU more than 45% in average at night. In summer, this increase day. These severe rainfalls are closely associated with LLJ. is considerably enhanced by the transport of water vapor 7KHDXWKRUVIRXQGDOLNHOLKRRGRIZLWK//-ZLWK IURPWKH*XOIRI0H[LFRWRWKHFHQWUDOSDUWRIWKH8QLWHG intensities of the order of 12.5 ms-1, which occurred at the OHYHORIK3DDQGKRXUVLQDGYDQFHRIWKHKHDY\ 5HFHLYHG$FFHSWHG rainfall events. *author for correspondence: [email protected] When LLJ were present on the island of Taiwan, a prob- 3o0DO(GXDUGR*RPHV&(3 ability estimate had a likelihood of 91% between precipitation 6mR-RVpGRV&DPSRV63±%UD]LO events and the LLJ. J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 2, pp. 227-235, Apr.-Jun., 2012 227 Corrêa, C.S. /DFNPDQQ GLVFXVVHVWKHFRQWULEXWLRQWKDWWKHmass and energy even with lower magnitude speeds than DGLDEDWLFSRWHQWLDOYRUWLFLW\SURGXFHGLQWKHPD[LPXPLQWHQ- a LLJ acting on synoptic scales typical of mesoalpha (Į) sity of LLJ. This potential link between the bands of front and mesobeta (ȕ), correspondinG to spatial scales between precipitation and adiabatic redistribution of potential vortic- DQGNP ity in the horizontal structure of the winds that accompany )ORZVDQG//-LQWKHYHUWLFDOZLQGSUR¿OHLQORZOHYHOV WKH//-DFWLQJGLUHFWO\RQWKHLQWHQVLW\RIWKHVH0DGGR[ in the troposphere have different spatial and temporal and Doswell III (1992) showed that the PBL may produce scales, featuring a wealth of combinations of structures heat by convection and by condensation, and heat advection in PBL and the lower atmosphere, connectinG with meso in the lower troposphere. to continental scale. This dynamic structure at low atmo- This process is associated with the circulations of the type sphere levels results in a layered structure, in which there 6WUHDPV//-ZKLFKSHUIRUPWKDWWUDQVSRUWRIVHQVLEOHDQG LVERWKLWVLQÀXHQFHDWDQLQWHUPHGLDWHOHYHO K3D DV latent heat in the lower atmosphere, dominating the differ- WKHORZHVWOHYHORIDURXQGK3DIRUFRQYHFWLYHV\VWHPV ential vorticity advection in the middle troposphere, forcing over Rio Grande do Sul. An important effect of LLJ is the upward vertically, resulting in the organization of convective daily cycle of moisture as water vapor, and the convergence events and generating MCS. of transport within the PBL implies a kind of moisture Uccellini and Johnson (1979) show that the hiGh level jet storage over large areas and basins. These can generate (HLJ) and LLJ can often be coupled by the adjustments of the meteoroloGical phenomena, such as restricted visibility by vertical mass, which occurs with the spread of HLJ. haze and fog and cloud layers and type as low stratus and This transport in the lower troposphere helps creatinG a stratucumulus. In cases where there is a positive balance, favorable environment for the development of severe thun- this moisture storaGe becomes a source of water vapor for derstorms, especially when the interaction of the jets occurs future convection occurrence. Therefore, this structure WKURXJKWKHLQWHUVHFWLRQRIWKHD[HVSHUSHQGLFXODURFFXUULQJ GDLO\WUDQVSRUWSOD\VDQH[WUHPHO\LPSRUWDQWUROHLQZDWHU within the region's output of HLJ. balance of a watershed in middle latitudes. In South America, the work of Abdoulaev et al. (1996) 7KHUHDUHIHZVFLHQWL¿FVWXGLHVOLQNLQJWKH//-HYHQWVZLWK VKRZHGWKDWWKH0&6PD\EHUHVSRQVLEOHIRUDVLJQL¿FDQW high rainfall, and the majority of studies on this topic are case portion of precipitation that occurs in Southern Brazil, occur- ones with reanalysis data of global models, which according ring in at least 13 events per year, with intense rainfall and WR%HUEHU\DQG&ROOLQL OLPLWVWKHH[SORLWDWLRQRIUHVXOWV may be associated with LLJ intense. due to low resolution of the data. Abdoulaev et al VWXG\LQJQRQOLQHDUV\VWHPV 'H %DUURV DQG 2\DPD DQDO\]HG WKH ZHDWKHU with mesoscale severe convection, observed the occur- systems associated with the occurrence of precipitation in UHQFHRIDKLJKUDLQIDOOSUREDELOLW\H[FHHGLQJPPKDW WKH$OFkQWDUDODXQFKEDVHEHWZHHQDQG,WDLPHG about 6 oclock in the morninG, with a seasonal variability at characterizinG the systems associated with precipitation between the beGinninG and end of the convective cells. In HYHQWVLQWKH$OFkQWDUD/DXQFK&HQWHU &/$ EHWZHHQ summer, on averaGe, the precipitations have a cycle of 6 DQGXVLQJWRWDOKRXUVRISUHFLSLWDWLRQ1&(3UHDQDO\VLV WRKRXUVDQGPRVW0&6HQGOLIHEHWZHHQDQG GDWDRI1&(31&$5EULJKWQHVVWHPSHUDWXUHRIWKHVDWHOOLWH hours. This led Abdoulaev et al WRFRQFOXGHWKDW *2(6DQGORQJZDYHUDGLDWLRQ7RWKLVHQGZHGH¿QHG the cycle of niGht and early morninG storms are amplified criteria to identify the weather systems of larGe, meso and and modulated by the converGence of water vapor, which local scale precipitation associated with the CLA, the results is mainly characterized by the LLJ. ZHUHWKDWRIWKHSUHFLSLWDWLRQSURFHVVHVZHUHVWUDWLIRUPHG ,Q5LR*UDQGHGR6XO&RUUrD REVHUYHGLQUDGLR- GHULYHGDQGFRQYHFWLYH sonde data held in Porto Alegre and Uruguaiana the dynamic This paper attempts to test the methodoloGy of Geosta- VWUXFWXUHRI6WUHDPV//-LQWKHWUDQVSRUWSURFHVVDWORZOHYHOV WLVWLFVFDOFXODWLQJWKHVHPLYDULRJUDPRIPD[LPXPUDLQIDOO Flows in the vertical wind profile can be defined as and usinG it in future researches to the reGion of Alcântara, streams that have varying speeds of the order of 5 ms-1 in Maranhão. The use of data observed in this study, by WR//-RQHV DERXWPV-1), and they do not also present FDOFXODWLQJWKHVHPLYDULRJUDPRIPD[LPXPSUHFLSLWDWLRQ the vertical structure of the jet. The flows are significant is an attempt to identify spatial and temporal patterns in because they may be associated with the convergence of SUHFLSLWDWLRQPD[LPXP 228 J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 2, pp. 227-235, Apr.-Jun., 2012 6WDWLVWLFDO$QDO\VLVRI6SDWLDODQG7HPSRUDO9DULDELOLW\RI0D[LPXP3UHFLSLWDWLRQ(YHQWVRQWKH5LR*UDQGHGR6XO DATA AND METHODOLOGY