Holmes-Smith, Carmen

Project title: Seasonal climatology study of diurnal, semidiurnal, and terdiurnal components of atmospheric tide from reanalysis

Department: Earth and Ocean Sciences

Faculty supervisor: Dr. Adam Monahan

"Thermally-driven atmospheric tides are hemispheric-scale phenomena strongly influenced by local mesoscale and boundary layer processes. Global characterization of atmospheric tides can make use of surface pressure observations from operational weather stations (irregularly distributed in space, with large areas without observations) or spatially-uniform reanalysis products. A substantial limitation of past reanalysis-based analyses has been their relatively coarse temporal resolution (typically 6-hourly). The recently produced Modern Era Retrospective Analysis for Research and Application, version 2 (MERRA-2) provides temporally and spatially high-resolution (respectively hourly and 0.625 x 0.5 degrees) representations of sea level pressure and surface pressure. This research project will use the MERRA-2 data to characterize the global distributions of amplitude and phase of the diurnal, semidiurnal, and terdiurnal tidal components of sea level pressure and surface pressure. These results will be compared to previous analyses using station data and earlier generation reanalysis products. Differences between the new and earlier results will be interpreted in terms of the effects of interpolation and model resolution."