TY  - JOUR
AU  - Ploeger, Felix
AU  - Birner, Thomas
AU  - Charlesworth, Edward
AU  - Konopka, Paul
AU  - Müller, Rolf
TI  - Moist bias in the Pacific upper troposphere and lower stratosphere (UTLS) in climate models affects regional circulation patterns
JO  - Atmospheric chemistry and physics
VL  - 24
IS  - 3
SN  - 1680-7316
CY  - Katlenburg-Lindau
PB  - EGU
M1  - FZJ-2024-01693
SP  - 2033 - 2043
PY  - 2024
AB  - Water vapour in the upper troposphere and lower stratosphere (UTLS) is a key radiative agent and a crucial factor in the Earth's climate system. Here, we investigate a common regional moist bias in the Pacific UTLS during Northern Hemisphere summer in state-of-the-art climate models. We demonstrate, through a combination of climate model experiments and satellite observations, that the Pacific moist bias amplifies local long-wave cooling, which ultimately impacts regional circulation systems in the UTLS. Related impacts involve a strengthening of isentropic potential vorticity gradients, strengthened westerlies in the Pacific westerly duct region, and a zonally displaced anticyclonic monsoon circulation. Furthermore, we show that the regional Pacific moist bias can be significantly reduced by applying a Lagrangian, less-diffusive transport scheme and that such a model improvement could be important for improving the simulation of regional circulation systems, in particular in the Asian monsoon and Pacific region.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001190484800001
DO  - DOI:10.5194/acp-24-2033-2024
UR  - https://juser.fz-juelich.de/record/1023129
ER  -