Data assimilation Forecasting Kalman filters Weather forecasting Aneroid altimeters Boundary layers Data acquisition Digital storage Ensemble Kalman Filter Ensemble Kalman filter Ensemble perturbation Ensemble prediction systems Floods Gages Kalman filter Mathematical and statistical techniques Meteorological instruments Meteorology Model evaluation/performance Model initialization Models and modeling Numerical models Numerical weather prediction/forecasting Observational errors Quality control Radio altimeters Satellite altimeter Satellite altimeter data Satellites South America