CIMA   09099
CENTRO DE INVESTIGACIONES DEL MAR Y LA ATMOSFERA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Estimation of soil moisture-precipitation interactions in South America using the Global Land Data Assimilation System
Autor/es:
P. SPENNEMANN; C. SAULO
Lugar:
Montevideo
Reunión:
Conferencia; WCRP-LACC; 2014
Institución organizadora:
WCRP
Resumen:
The main objective of
this study is to identify regions where soil moisture anomalies influence subsequent
precipitation and evapotranspiration anomalies, during the warm season in South
America aimed at developing alternative tools for seasonal prediction, based on
soil states. A statistical methodology, based on a ratio of lagged correlations,
is applied to estimate the interactions between these variables using the
Global Land Data Assimilation System (GLDAS) dataset. Possible impacts of remote
forcing (e.g. ENSO) on these interactions are also examined. Our focus has been set over two sub-regions: Southeastern
South America (SESA) and the continental part of the South Atlantic Convergence
Zone (SACZ). Over tropical regions, parts of SACZ and in the southern part of
South America positive and significant feedbacks between soil moisture and
precipitation are found. Instead, significant negative feedbacks are found over
SESA. The influence of ENSO over the soil moisture-precipitation coupling
strength signal is evident over tropical regions. Likely physical mechanisms
involved in the land surface-atmosphere interactions, the remote influence of
ENSO and the role of precipitation persistence over extratropical regions will
be discussed: it has been found that soil moisture-precipitation hot spots are
sometimes largely driven by large precipitation autocorrelation at monthly
scales. Despite that this methodology cannot be used to determine a precise
causal-effect relationship between soil moisture and precipitation, this study
documents a valuable first order approximation of land surface-atmosphere
interactions over South America that complements pre-existing works.