Comparison of MERRA and MERRA2 Climatology Based on Events Derived from Applying a Visibility Criterion Related to Blizzard-like Conditions
Abstract
A superbly optimized method has been developed for a Big Data technology, whereby events of Earth Science phenomena can be identified and tracked with unprecedented efficiency. An event in this context is an episode of a phenomenon evolving in both space and time and not just a snapshot in time. This innovative method is applied to 36 years of both MERRA and MERRA-2 datasets, with a visibility criterion related to blizzard-like conditions. Visibility is estimated using a formula that takes snowfall rate and near-surface winds into consideration. MERRA-2 features additional observing systems and improvements to the hydrological cycle not present in the original MERRA atmospheric reanalysis, including the forcing of the land surface with observations-based precipitation fields and the implementation of a moisture constraint, preventing an imbalance in global precipitation and surface evaporation. MERRA-2 also features numerous advancements in the underlying model, such as in the surface layer and boundary layer parameterizations and in the cumulus convection scheme. The data assimilation has been updated to the latest Gridpoint Statistical Interpolation version and includes global dry mass constraints that help minimize spurious temporal variability effects. Thus, we report and compare in this presentation event-based statistics derived from MERRA and MERRA-2, highlighting the differences, especially the superiorities, of MERRA-2. We also identify aspects of MERRA-2 that may need further improvements.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.H23F1649K
- Keywords:
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- 3354 Precipitation;
- ATMOSPHERIC PROCESSESDE: 1854 Precipitation;
- HYDROLOGYDE: 1855 Remote sensing;
- HYDROLOGYDE: 4303 Hydrological;
- NATURAL HAZARDS