Sensitivity of simulated Convectively Coupled Kelvin Waves to physics schemes and resolution with an idealized tropical channel

This work analyses simulated Convectively Coupled Kelvin Waves (CCKW) and their sensitivity to different cumulus and boundary layer schemes as well as horizontal resolution using the ARW-WRF model. The simulations are performed in a “tropical channel” domain, using the aquaplanet intercomparison project “observed” SST profile, with 40km resolution over a domain 13000kmx13000km in size. Several experiments are performed using: a) the updated Mellor-Yamada-Nakanishi-Niino (MYNN2) and Yonsei University (YSU) PBL schemes; b) the Betts-Miller-Janjic (BMJ) and Kain-Fritsch (KF) cumulus schemes; c) activation (or not) of a nested channel in a 16-degree tropical belt with 8km spacing, where convection is solved explicitly. Composites for different variables are calculated following the CCKW as it propagates eastward. Preliminary results show that when the model is run with the nested channel using resolved convection, the region of convection and precipitation associated to the CCKW expands both zonally and meridionally, and also a single ITCZ pattern is obtained, in contrast to a double ITCZ for other cases. These results are compared to other simulations and observations.