Seminar: Joowan Kim
Please join us tomorrow, Wednesday at 14:35 in Burnside 934 for a student seminar by Joowan Kim. Abstract is as follows:
Thermal characteristics of the tropical tropopause layer in CMIP5 models: historical simulations
The climatology and variability of temperatures in the tropical tropopause layer are investigated in 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models for historical simulations. The climatology of 100-hPa temperatures compare well with ERA-Interim reanalysis. The models possess reasonable temperature minima in the deep tropics, but some models also have a warm bias or a bias in the location of the temperature minima. The CMIP5 models generally capture the phase of the seasonal cycle in 100-hPa temperatures, but the amplitude of the seasonal cycle varies greatly among models. The interannual variability in 100-hPa temperature is associated with the El Niño-Southern Oscillation (ENSO) and volcanic forcing in observation and CMIP5 models. Most of models successfully capture the ENSO-related large scale response, but the response to volcanic forcing is overestimated in many models. On intraseasonal timescales, observed and modeled variability is dominated by equatorial waves (Kelvin, inertio-gravity, and mixed Rossby-gravity waves) and the Madden-Julian Oscillation (MJO). Most models show variability related to the equatorial waves, but significant biases are found in the phase speeds of the waves when compared to ERA-Interim. The MJO signature is weak and non-distinguishable from the Kelvin wave power in most CMIP5 models.