Impacts of Varying the Spatial Density and Temporal Frequency of Surface Pressure Observations on Atmospheric Uncertainty

Thursday, November 21, 2013 - 10:45am - 11:10am
Lind 305
Lili Lei (National Center for Atmospheric Research)
To investigate the impacts of observing only surface pressure, the Data Assimilation Research Testbed and the Community Earth System Model (DART/CESM) are used for observing system simulation experiments with the ensemble Kalman filter (EnKF). An empirical localization function (ELF) is used to effectively spread the surface pressure observations in the vertical. The ELF is defined to minimize the root mean square (RMS) difference between the truth and the posterior ensemble mean for state variables. The spatial density and temporal frequency of the observations are varied. The land surface and sea ice models are fully active and coupled to the atmosphere model but the ocean is specified. Surface pressure observations can constrain uncertainty throughout the entire depth of the troposphere. However, the atmospheric boundary layer sometimes has large uncertainty over land. In general the error of the entire depth of the troposphere can be better constrained with increased observation density and frequency.