author = "Saulo, A. Celeste and Seluchi, Marcelo Enrique and Nicolini, 
          affiliation = "{CPTEC-INPE-Cachoeira Paulista-12630-000-SP-Brasil}",
                title = "A case study of a Chaco Low Level Jet event",
              journal = "Monthly Weather Review",
                 year = "2004",
               volume = "132",
               number = "11",
                pages = "2669--2683",
                month = "nov.",
             abstract = "This paper concentrates on the analysis of the life cycle of the 
                         low level jet (LLJ) during a summer Chaco Jet event. This is 
                         accomplished through the use of the Eta/CPTEC (Centro de 
                         Previs{\~a}o del Tempo e Estudos Clim{\'a}ticos) regional model, 
                         in order to obtain high temporal and spatial detail of the main 
                         processes taking place. Both the low level circulation and the 
                         geopotential height evolution at different latitudes are analyzed 
                         to provide a more detailed description of the effects of 
                         topography and differential warming on the evolution of this 
                         current. This study shows that the life cycle of the particular 
                         event analyzed, is not the same at the different latitudes swept 
                         by this well organized northerly current, expanding from 15šS to 
                         32šS during two consecutive days. A common feature to all the 
                         examined latitudes is the presence of a diurnal cycle linked to 
                         local effects which is more evident during the first day and a 
                         half of the simulation. This cycle was identified not only by a 
                         nocturnal maximum of the wind, but also by the oscillations of the 
                         geostrophic wind close to the surface in response to differential 
                         warming over sloping terrain. However, during the second day, the 
                         diurnal oscillation is superseded by synoptic scale forcing. The 
                         meridional growth of this northerly current reacts basically to a 
                         deepening of the Northwestern Argentina Low, consequently being a 
                         geostrophic response to a synoptic perturbance. However, during 
                         the final stages of this event, a northerly wind area located over 
                         the 3 southern tip of the current, which notably increases the 
                         northerlies penetration toward higher latitudes, develops. This 
                         last extension is mainly due to a component of ageostrophic 
                         origin. Evidence is provided in support to the hypothesis that 
                         this secondary development as a feedback between the LLJ and the 
                         precipitation at the exit region.",
           copyholder = "SID/SCD",
                 issn = "0027-0644",
             language = "en",
           targetfile = "Saulo_A case study of a Chaco.pdf",
        urlaccessdate = "20 jan. 2021"