Large Uncertainties in Estimation of Tropical Tropopause Temperature Variabilities Due to Model Vertical Resolution

Abstract

AbstractTropopause temperature (TPT) is a useful indicator and a key component of climate change. Well simulating its value and seasonal‐to‐decadal variability by climate models is still challenging. How the vertical resolution influences the representation of TPT and its response to a climate forcing is largely unknown. This study investigates TPT responses to sea surface temperatures using a series of model simulations in various vertical resolution. With high vertical resolution (HV‐Res), the model gives a better representation of tropical TPTs in absolute values and seasonal variations. The corresponding changes in TPTs associated with sea surface temperature anomalies (El Niño–Southern Oscillation and Pacific Decadal Oscillation) are 30% stronger and more realistic in the HV‐Res model. Such improvements may get benefits from better representations of equatorial waves with more realistic structure and stronger interannual variations. A proper vertical resolution is therefore essential to well simulate the stratosphere‐troposphere coupling and should be used in climate change assessment.