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Case studies on turbulence in different tropopause folds

Tropopause folds are known as areas of enhanced stratosphere-troposphere exchange. These exchange processes are governed by turbulent mixing in the upper-tropospheric and lowerstratospheric shear zones around the tropopause jet. Since the 1970s, turbulence is also predicted to enhance the ageostrophic circulation around the jet, which leads to the formation of the tropopause fold in an upper-level jet-front system. This claim was recently confirmed by a numerical weather prediction study using the ECMWF-IFS.