@InProceedings{AngelisMachSali:2006:ImLoLe,
               author = "Angelis, Carlos Frederico and Machado, Luiz Augusto Toledo and 
                         Salio, Paola",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Impacts of the Low Level Jets on the precipitation over southern 
                         South America",
            booktitle = "Proceedings...",
                 year = "2006",
               editor = "Vera, Carolina and Nobre, Carlos",
                pages = "961--966",
         organization = "International Conference on Southern Hemisphere Meteorology and 
                         Oceanography, 8. (ICSHMO).",
            publisher = "American Meteorological Society (AMS)",
              address = "45 Beacon Hill Road, Boston, MA, USA",
             keywords = "low level jet, LLJ, precipitation, moonson, South America.",
             abstract = "Observational studies using five-year data of daily precipitation 
                         and Low Level Jets (LLJ) events occurred over the south of South 
                         America revealed the rainfall behaviour in an area from latitudes 
                         10°S to 40°S and longitudes 70°W to 40°W during the period 
                         2000-2004. Rain gauges located within this area were gridded at 
                         1°x 1° and provided daily precipitation measurements during this 
                         period. The LLJ events were assessed from Global Data Assimilation 
                         System (GDAS) analyses, which revealed the existence of three 
                         different types of jets: CJE (Chaco Jet Event) whose jets exits 
                         extend to latitudes higher than 25°S, NCJE (No Chaco Jet Event) 
                         whose jets exits extend to latitude 25°S only and LLJA (Low Level 
                         Jet-Argentina) which occurs over latitudes higher than 25°S. A 
                         fourth type of event named NADA was defined as the occurrence of 
                         any other event different from the previous three. Descriptive 
                         statistics show that CJE, NCJE, LLJA and NADA account for 20.25%, 
                         18.52%, 10.37% and 50.85%, respectively, of all events occurred 
                         during the study period (1213 days). The mean monthly rainfall 
                         associated with each jet type over the entire study area was equal 
                         to 1032.51, 1333.13, 879.65 and 1212.16 mm/month when CJE, NCJE, 
                         LLJA and NADA events, respectively, occurred. It is interesting to 
                         note that despite showing the lowest frequency of occurrence 
                         (10.37%), the NCJE produced the highest amount of rain. The 
                         response of rainfall after a jet event revealed the areas where 
                         precipitation is enhanced during the observed period. It seems 
                         that CJE (NCJE) tends to intensify precipitation in areas over 
                         south-eastern Brazil (southern Brazil, north-eastern Argentina and 
                         eastern Paraguay). Daily rainfall for those areas presents values 
                         as high as 15 mm/day (25 mm/day). It also seems that LLJA enhances 
                         precipitation over northern Argentina with daily values rarely 
                         exceeding 10 mm/day, and NADA enhances precipitation over northern 
                         and central Argentina with daily values always lower than 6 
                         mm/day. The seasonal variation of precipitation shows maximum 
                         rainfall values during the quarter Sep/Oct/Nov as a result of the 
                         CJE and NCJE maximum occurrence. Particularly during the quarter 
                         Dec/Jan/Feb LLJA reaches its minimum of occurrence and the 
                         rainfall associated with this type of jet display values higher 
                         than the climatological average over the centre and north of 
                         Argentina. This research provides evidences of the impacts of 
                         different LLJ events on the precipitation regime over southern 
                         South America. Although consistent with previous studies, no 
                         interactions between LLJ and other phenomena like the South 
                         Atlantic Convergence Zone (SACZ) and the northwards penetration of 
                         frontal colds are being considered by this study.",
  conference-location = "Foz do Igua{\c{c}}u",
      conference-year = "24-28 Apr. 2006",
           copyholder = "SID/SCD",
             language = "en",
         organisation = "American Meteorological Society (AMS)",
                  ibi = "cptec.inpe.br/adm_conf/2005/11.01.00.06",
                  url = "http://urlib.net/ibi/cptec.inpe.br/adm_conf/2005/11.01.00.06",
           targetfile = "961-966.pdf",
                 type = "Monsoon systems and continental rainfall",
        urlaccessdate = "19 abr. 2024"
}