Seminar by Prof. Boualem KHOUIDER - University of Victoria, Canada
Title: Improving the tropical modes of atmosphere variability with a stochastic parameterization of convection
Abstract:
Organized convection in the tropics is organized on a hierarchy of scales ranging from the convective cell-individual cloud of 1 to 10 km, to cloud clusters and superclusters of 100’s and 1000’s km, to planetary scale disturbances such as the Madden Julian oscillation and monsoon intraseasonal oscillations. State-of-the-art climate models do not properly simulate the associated synoptic and planetary scale wave patterns and the inherent precipitation variability as well as the global climatology, which hinders the fidelity of medium to long term weather and climate predictions. This is due in large part to the underlaying cumulus parameterizations that are not designed to represent the interactions across temporal and spatiale scales between these convectively coupled coherent structures but instead are based on the quasi-equilibrium theory which assumes that convection is merely slaved to the large-scale/resolved dynamics. Instead a stochastic lattice system is utilized here to mimic the interactions of the multiple cloud types that characterize organized convection and thus the associated missing subgrid variability of cloud clusters and superclusters. When the so-called stochastic multicloud model is implemented in a climate model (NCEP’s Climate Forecasting System), the representation of the large-scale tropical modes of variability such as the MJO, the convectively coupled waves, and the monsoon intra-seasonal oscillations as well as the associated rainfall variability distributions has tremendously improved.
When: November 21, 2022 at 2:30 PM
Where: Conference room at RMI and online
Join Zoom Meeting
https://us02web.zoom.us/j/83496759955?pwd=LzFyN210R1JLTTRrMng0bXpWZm5zZz09
Meeting ID: 834 9675 9955
Passcode: 105807
