@Article{NobreGanVend:2023:ObSt,
               author = "Nobre, Jo{\~a}o Pedro Gon{\c{c}}alves and Gan, Manoel Alonso and 
                         Vendrasco, {\'E}der Paulo",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Effects of soil moisture and surface heat fluxes on the South 
                         American Monsoon System over West-Central Brazil: an observational 
                         study",
              journal = "Hydrology and Earth System Sciences Discussions",
                 year = "2023",
               volume = "2023",
                pages = "e198",
             abstract = "This study evaluated the relationship between different surface 
                         hydrometeorological variables and rainfall during the wet period 
                         of the South American Monsoon System (SAMS). A climatological 
                         study was performed for 30 rainy periods of the SAMS between the 
                         years 1991-2021 over the Central-West region of Brazil (WCB) 
                         (20-10\◦ S and 60-50\◦ W). The European Centre for 
                         Medium-Range Weather Forecasts Reanalysis 5th/ERA5 was used to 
                         understand, under different soil moist conditions (dry, 
                         intermediate, and wet), the hydrometeorological patterns and their 
                         impacts on SAMS during the three stages of the wet period: the 
                         development (September-October-November, SON), maturity 
                         (December-January-February, DJF), and weakening (March-April-May, 
                         MAM) South American monsoon quarters. The results show that along 
                         with an increase (decrease) in rainfall during the rainy season, 
                         there is also a significant increase (decrease) in both surface 
                         and subsurface volumetric soil moisture (\θ) for the wet 
                         (dry) soil condition periods. However, the surface heat flux 
                         composites showed that the latent heat fluxes to the atmosphere 
                         (Hl) significantly exceeds the climatology during the SAMS 
                         development quarters (SON) for the wet soil group. In contrast, 
                         for the dry soil group, the significant increase of Hl, compared 
                         to the climatology, over the WCB occurred only during the SAMS 
                         maturity quarters (DJF), representing, in this last case, a 
                         significant injection of latent heat and consequently delayed 
                         evaporation (EV P) compared to rainy periods with wet soil, due to 
                         the low soil moisture content and the prevalence of dry convection 
                         over WCB. Regarding the sensible heat fluxes (Hs), it was observed 
                         drier (wetter) soils tend to exhibit values above (below) the 
                         climatological mean throughout all stages of SAMS evolution over 
                         the WCB. The 2-m air temperature (T2m) and planetary boundary 
                         layer height (P BLH) anomaly composites showed that for the wet 
                         (dry) soil group and with significant rainfall above (below) the 
                         climatological mean over the WCB, all evolution quarters were 
                         marked by a significant decrease (increase) in T2m and P BLH 
                         anomalies. Regarding the mechanisms of direct feedback between 
                         surface variables and rainfall associated with the SAMS, 
                         significant direct correlations were also observed between the 
                         mean rainfall of the SAMS rainy season and the mean values of 
                         active days duration (Dad), Hl 20 , Hs and the surface Soil 
                         Moisture Condition Index (SMCI1).",
                  doi = "10.5194/hess-2023-198",
                  url = "http://dx.doi.org/10.5194/hess-2023-198",
                 issn = "1812-2108",
             language = "en",
           targetfile = "hess-2023-198.pdf",
        urlaccessdate = "27 abr. 2024"
}