Sep 1, 2010

Diagnosis of Zonal Mean Relative Humidity Changes in a Warmer Climate

Jonathon S. Wright and Adam Sobel
Journal of Climate: Vol 23, No 17
  • Examines the zonal mean relative humidity response to a doubling of CO2 in a climate model using a global climate model and an offline tracer transport model
  • Finds the responses of the tropical and subtropical relative humidities to be largely dependent on circulation and transport changes, particularly a poleward expansion of the Hadley cell, a deepening of the height of convective detrainment, a poleward shift of the extratropical jets, and an increase in the height of the tropopause
  • Finds relative humidity changes near the extratropical tropopause and in the lower troposphere are largely dependent on changes in the distribution and gradients of temperature
  • Finds increases in relative humidity near the extratropical tropopause in both hemispheres are coincident with increases in the occurrence of local saturation and high cloud cover