University of North Dakota Faculty/Staff Newsletter

Jet Propulsion Laboratory scientist to present seminar Nov. 29

Jonathan Jiang, research scientist, with the Jet Propulsion Laboratory in Pasadena, will present a seminar titled “Evaluation and Regime-dependent Error Diagnosis of Cloud and Water Vapor Simulations in Climate Models Using NASA A-Train Satellite Observations” at 3 p.m. Thursday, Nov. 29, in 106 Streibel Hall. Faculty and students are encouraged to attend.

Abstract: Using NASA "A-Train" satellite observations, we evaluate the accuracy of cloud water content (CWC) and water vapor mixing ratio (H2O) outputs from ~20 climate models submitted to the CMIP5, and assess improvements relative to their counterparts for the earlier CMIP3. We find more than half of the models show improvements from CMIP3 to CMIP5 in simulating column-integrated cloud amount, while changes in water vapor simulation are insignificant. For the CMIP5 models, the model spreads and their differences from the observations are much larger in the upper troposphere than in the lower or middle troposphere. Numerical scores are used to compare model performances in regards to spatial mean, variance and distribution of CWC and H2O over the tropical oceans. Model performances at each pressure level are ranked according to the average of all the relevant scores for that level. We further developed a diagnostic framework to decompose the cloud simulation errors into the large-scale errors, cloud parameterization errors and co-variation errors. We find that the cloud parameterization errors contribute predominantly to the total errors for all models.

-- Wanda Seyler, Atmospheric Sciences, 777.3884, seyler@atmos.UND.edu.


Tagged as: ,