How Realistic are Hydrometeorological Processes from Reanalysis? – Intercomparison of Multiple Reanalysis Products using in situ Observational Data (Invited talk)

Reanalysis products provide comprehensive and physically consistent datasets of the earth system, and hence are widely used in weather, climate, and hydrometeorological studies (including extreme and high-impact events). Over land, however, almost all of the below- and above-ground state variables and fluxes are model-generated with very limited constraints from observations. Therefore it is critically important to rigorously evaluate various reanalysis products using in situ observations over different climate regimes.

In this presentation, we will review our work in several recent papers on this issue using in situ observations from different regions of the world. First, we will assess the near-surface atmospheric fields from reanalysis products that drive land surface processes, such as precipitation, radiative fluxes, and temperature, over different regions (e.g., North America, China, and Greenland). Second, land surface variables will be evaluated, such as snow water equivalent, turbulent fluxes, and skin temperature. An innovative method to address the spatial heterogeneity issue in snow water equivalent will also be presented. Third, below-ground variables will be intercompared, such as soil temperature and moisture. Finally, coupled evaluation of below- and above-ground processes and their seasonal cycle will be used to shed new light on reanalysis products.