@InProceedings{Graciela:2006:StEvLo,
               author = "Graciela, Ulke Ana",
          affiliation = "Universidad de Buenos Aires, Fac. de Cs. Exactas y Naturales, 
                         Depto. de Cs. de la Atm{\'o}sfera y los Oc{\'e}anos, 
                         Pabell{\'o}n II Piso 2do, 1428 Ciudad Universitaria, Buenos 
                         Aires, Argentina",
                title = "Structure and evolution of the lower troposphere in the presence 
                         of a SALLJ event",
            booktitle = "Proceedings...",
                 year = "2006",
               editor = "Vera, Carolina and Nobre, Carlos",
                pages = "1089--1095",
         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 = "South American Low Level Jet, mesoscale modeling, model 
                         evaluation, complex terrain.",
             abstract = "The South American Low level Jet Experiment (SALLJEX) was an 
                         international field campaign carried out to improve the 
                         understanding of a wind maximum that develops East of the Andes 
                         (the South American Low level Jet (SALLJ)). It took place from 15 
                         November 2002 to 15 February 2003. The observational 
                         meteorological network was enhanced with pilot balloon and 
                         radiosonde releases with high spatial and temporal resolution. 
                         During selected situations an instrumented aircraft flew and 
                         documented the three-dimensional structure of the atmosphere. The 
                         SALLJ is a key feature of South American climate and plays an 
                         important role as a transport mechanism. It develops and evolves 
                         as a result of physical forcing on various temporal scales and 
                         surface and topographic conditions. In addition, interacts with 
                         different meteorological circulations. Even though the field study 
                         provided the largest available data set up to the present; the 
                         information remains somehow limited when the objective is to study 
                         the detailed atmospheric structure and evolution. A numerical 
                         mesoscale model could give this information, but in order to use 
                         the results of the simulations as a tool to better understand a 
                         particular subject, a proper evaluation with observational data is 
                         required. Data from one of the days of SALLJEX were used to 
                         investigate the structure and evolution of the SALLJ and to 
                         evaluate the meteorological fields and related parameters as 
                         simulated by a mesoscale model. Observations from selected tracks 
                         of the NOAA-P3 aircraft, which flew across and along the SALLJ 
                         core were used. The mesoscale model used is the BRAMS 3.2. The 
                         simulations considered two-way interactive nested grids. Three 
                         grids with horizontal spacing of 80, 20 and 5 km were used. The 
                         outermost grid covered South America while the innermost grid 
                         encompassed Bolivia and Northern Paraguay. The simulations covered 
                         from 1200 UTC 5 to 7 February 2003. The five lateral boundary 
                         points in the largest domain were nudged towards Global Data 
                         Assimilation System (GDAS) analysis provided by the National 
                         Centers for Environmental Prediction (NCEP), with one-degree 
                         horizontal resolution at 6-h intervals. This analysis also gave 
                         the initial conditions. The topography was derived from the United 
                         States Geological Survey (USGS) data set. Soil moisture 
                         initialization for the present study provided a heterogeneous 
                         field. Alternative simulations were carried out with different 
                         turbulence parameterization schemes. In some of the simulations 
                         terrain following vertical coordinates were used, and in others, 
                         the shaved-ETA coordinate was selected. Spatial and temporal 
                         variations of basic variables (temperature, humidity and wind) 
                         were studied and the observed and modeled patterns were analyzed 
                         and compared. Derived variables that characterize the atmospheric 
                         boundary layer structure were also obtained. Data allowed an 
                         evaluation of BRAMS in complex terrain with a relatively high 
                         horizontal resolution. In general, simulations agreed well with 
                         the observed values and behavior. Further research is needed to 
                         improve some aspects related to the modeled water vapor content, 
                         atmospheric stability and boundary layer depth.",
  conference-location = "Foz do Igua{\c{c}}u",
      conference-year = "24-28 Apr. 2006",
             language = "en",
         organisation = "American Meteorological Society (AMS)",
                  ibi = "cptec.inpe.br/adm_conf/2005/10.31.23.35",
                  url = "http://urlib.net/ibi/cptec.inpe.br/adm_conf/2005/10.31.23.35",
           targetfile = "1089-1096.pdf",
                 type = "Monsoon systems and continental rainfall",
        urlaccessdate = "20 maio 2024"
}