Abstract
Currently, there is an increase in the number of low orbit satellites dedicated to radio occultation of GPS signals. The MetOp-B is one of these new satellites, but it has not been explored in the data assimilation performed in Brazil. In order to include this source of observation in the database used in the assimilation of the CPTEC/INPE and evaluate its impact in the performance of the Atmospheric Global Circulation Model used operationally at the center, an experiment with data from January and August 2014 was executed. The results were compared with another experiment without assimilating those data, which showed that the inclusion of the MetOp-B refractivity profiles, has impacted beneficially the assimilation of more data from the other satellites in use, such as COSMIC, TerraSAR-X and MetOp-A. The most prominent results were observed in August, with root mean squared gain values greater than 40% in the state variables for the 24-h forecast over the Southern Hemisphere, variables that are directly related to the refractivity values. Beyond that, the anomaly correlation coefficient values over South America indicated that, adding the MetOp-B data, the zonal and meridional wind components at 250 hPa were indirectly impacted, showing the importance of assimilate such data.
Keywords:
GPS radio occultation; data assimilation; MetOp-B
