Impact of assimilation of LASE and dropwindsonde data sets during NAMMA field campaign

The impacts of dust loaded, Saharan Air Layer (SAL) during the life cycle of African Easterly Wave (AEW) is a many faceted scientific problem. It entails possible radiative effects of dust aerosols, impacts of dust on cloud physics- the cloud nuclei of condensation, advective effects, i.e. intrusions of dry dusty air versus humid air into the interior of storms. This study addresses several such AEWs of the eastern Atlantic Ocean where we have made use of special aircraft reconnaissance data sets, that include wind and humidity profiles in the vertical. A high resolution mesoscale model WRF-ARW is used in this study. The WRF-3DVAR is used to assimilate new aircraft data obtained during the NAMMA field campaign from the LASE and dropwindsondes. Sensitivity experiments are done to see how the assimilation impacts the analysis and hence the forecasts. The impact of wind data along with the moisture data from dropwindsondes are also compared to the assimilation done alone with the moisture data obtained from LASE instrument. We see that most of the time the analysis improved as more and more data are assimilated. Our results show that the inclusion of humidity profiling distinguishes between developing versus non developing AEWs from the use of these additional data sets.