@InProceedings{SapucciMoniMach:2007:SeVaSt,
               author = "Sapucci, Luiz Fernando and Monico, Jo{\~a}o Francisco Galera and 
                         Machado, Luiz Augusto Toledo",
          affiliation = "Instituto Nacional de Pesquisas Espaciais,(INPE/CPTEC) and 
                         Universidade Estadual Paulista-Faculdade de Ci{\^e}ncias e 
                         Tecnologia, Presidente Prudente, SP , Brazil and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE/CPTEC)}",
                title = "Seasonal Variability Study of the tropospheric zenithal delay in 
                         the South America using regional numerical weather prediction 
                         model",
            booktitle = "Anais...",
                 year = "2007",
         organization = "Joint Assembly.",
            publisher = "AGU",
              address = "Acapulco, M{\'e}xico",
             keywords = "seasonal variability, tropospheric, South America, numerical 
                         weather prediction.",
             abstract = "In 2010 a new navigation and administration system of the air 
                         traffic, denominated CNS-ATM (Communication Navigation 
                         Surveillance - Air Traffic Management) should be running 
                         operationally in South America. This new system will basically 
                         employ the positioning techniques by satellites to the management 
                         and air traffic control. However, the efficiency of this new 
                         system demands the knowledge of the behavior of the atmosphere, 
                         consequently, an appropriated Zenithal Tropospheric Delay (ZTD) 
                         modeling in a regional scale. The predictions of ZTD values from 
                         Numeric Weather Prediction (NWP), denominated here dynamic 
                         modeling, is an alternative to model the atmospheric gases effects 
                         in the radio-frequency signals in real time. Brazilian Center for 
                         Weather Forecasting and Climate Studies (CPTEC) of the National 
                         Institute for Space Research (INPE), jointly with researchers from 
                         UNESP (Sao Paulo State University), has generated operationally 
                         prediction of ZTD values to South America Continent (available in 
                         the electronic address 
                         http:satelite.cptec.inpe.br/htmldocs/ztd/zenithal.htm). The 
                         available regional version is obtained using ETA model (NWP model 
                         with horizontal resolution of 20 km and 42 levels in the 
                         vertical). The application of NWP permit assess the temporal and 
                         spatial variation of ZTD values, which is an important 
                         characteristic of this techniques. The aim of the present paper is 
                         to investigate the ZTD seasonal variability over South America 
                         continent. A variability analysis of the ZTD components 
                         [hydrostatic(ZHD) and wet(ZWD)] is also presented, as such as 
                         discussion of main factors that influence this variation in this 
                         region. The hydrostatic component variation is related with 
                         atmospheric pressure oscillation, which is influenced by relief 
                         and high pressure centers that prevail over different region of 
                         the South America continent. The wet component oscillation is due 
                         to the temperature and humidity variability, which is also 
                         influenced by relief and by synoptic events like: the penetration 
                         the cold front from Antarctic pole into the continent and 
                         occurrence of humidity convergence zones. In South America there 
                         are two main convergence zones that has strong influence in the 
                         troposphere variability, the ITCZ (Inter Tropical Convergence 
                         Zone) and the SACZ (South Atlantic Convergence Zone) zones. These 
                         convergence zones are characterized by an extensive precipitation 
                         band and high nebulosity almost stationary. The physical processes 
                         associated with these convergence zones present strong impacts in 
                         the variability of ZWD values. This work aims to contribute with 
                         ZTD modeling over South America continent using NWP to identify 
                         where and when the ZTD values present lower predictability in this 
                         region, and consequently, minimizing the error in the GNSS 
                         positioning that apply this technique..",
  conference-location = "Acapulco, M{\'e}xico",
      conference-year = "22-25 May",
           copyholder = "SID/SCD",
             language = "en",
         organisation = "AGU",
           targetfile = "12-Sapucci_el.al_AGU2007_APRESENT-1.pdf",
        urlaccessdate = "24 abr. 2024"
}