Large-scale organized convection, particularly in the form of the Madden-Julian Oscillation (MJO), exerts significant impacts on a wide range of weather/climate phenomena. Current general circulation models (GCMs), unfortunately, are incapable of robustly representing these forms of variability. In particular, a well-accepted and comprehensive theory for the MJO is still elusive. This project seeks to address this challenge by fully characterizing the vertical structures of the MJO and convectively coupled equatorial waves (CCEWs), particularly diabatic heating, to better constrain theoretical understanding as well as to provide crucial validation information to the model development community.
Specifically, the investigators will (i) characterize the Tropical Rainfall Measuring Mission (TRMM) -estimated vertical latent heating structures associated with the large-scale and low-frequency CCEWs, including the MJO, and examine them in the context of the TRMM rainfall, Atmospheric Infrared Sounder (AIRS) temperature and moisture, and CloudSat cloud-type variations, with a particular focus on describing the spatial variability, seasonal modulation, event-to-event variability, and implications for our theoretical understanding; (ii) compare these heating and moist thermodynamic structures with values from the new reanalysis products to assess and characterize the uncertainties and shortcomings of both the satellite and model based products in regards to their representation of CCEWs; (iii) compare these heating and moist thermodynamic structures with values from a pair of traditional GCMs and a pair of GCMs utilizing multi-model framework to quantify the fidelity of the model's representation of CCEWs and provide feedback to the model development teams; and (iv) examine the dependence of the Rossby Wave emanation on the location and vertical profiles of the tropical heating structures.
The broader impacts of this project include (i) improvements in the mean structure and variability of tropical convective activity in our global climate/weather models, which will ultimately lead to improved skill of medium-to-extended range weather and seasonal climate predictions both in the tropics and extra-tropics, facilitate the development of the hitherto unexploited forecast potential at the subseasonal time scale, and reduce uncertainties associated with global model projections of climate change; (ii) the training of a graduate student in an area that is in high demand.
