The boreal winter response of the ocean mixed layer to the Madden–Julian oscillation (MJO) in the IndoPacific region is determined using in situ observations from the Argo profiling float dataset. Composite averages over numerous events reveal that the MJO forces systematic variations in mixed layer depth and temperature throughout the domain. Strong MJO mixed layer depth anomalies (.15 m peak ...

Although recent studies have examined the responses of annual- and seasonal-mean Madden-Julian oscillation (MJO) activity to global warming, little is known about seasonal cycle changes that determine timing peak MJO influence on local weather climate. By analyzing Community Earth System Model version 2 large ensemble at end 21st century, we report in both phase amplitude precipitation over tro...

Boreal-wintertime hindcasts in the Unified Forecast System with tropics nudged toward reanalysis improve United States (US) West Coast precipitation forecasts at Weeks 3–4 lead times when compared to those without nudging. To diagnose origin of these improvements, a multivariate k-means clustering method is used group into subsets by their initial conditions. One cluster characterized an initia...

The effect of clouds on climate remains the largest uncertainty in climate change predictions, due to the inability of global climate models (GCMs) to resolve essential small-scale cloud and convection processes. We compare preindustrial and quadrupled CO2 simulations between a conventional GCM in which convection is parameterized and a "superparameterized" model in which convection is explicit...

Title of Document: MADDEN-JULIAN OSCILLATION AND SEA SURFACE TEMPERATURE INTERACTIONS IN A MULTI-SCALE FRAMEWORK Lei Zhou, Ph. D., 2009 Directed By: Prof. Murtugudde, Department of Atmospheric and Oceanic Sciences/ESSIC The ocean-atmosphere coupling can play a role in initiating and sustaining the Madden-Julian Oscillations (MJOs), which are the major intraseasonal oscillations in the atmospher...

The role of air–sea coupling in the simulation of the Madden–Julian oscillation (MJO) is explored using two configurations of the Hadley Centre atmospheric model (AGCM), GA3.0, which differ only in F, a parameter controlling convective entrainment and detrainment. Increasing F considerably improves deficient MJO-like variability in the Indian and Pacific Oceans, but variability in and propagati...

The Madden-Julian oscillation (MJO) is the dominant mode of variability in the tropical atmosphere on intraseasonal timescales and planetary spatial scales. Despite the primary importance of the MJO and the decades of research progress since its original discovery, a generally accepted theory for its essential mechanisms has remained elusive. Here, we present a minimal dynamical model for the M...

[1] We investigate the modulation of aerosols by the Madden-Julian Oscillation (MJO) using multiple, global satellite aerosol products: aerosol index (AI) from the Total Ozone Mapping Spectrometer (TOMS) on Nimbus-7, and aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua and the Advanced Very High Resolution Radiometer (AVHRR) on NOA...

In Part I of this study it was shown that moving from a moisture-convergentto a relative-humidity-dependent organized entrainment rate in the formulation for deep convection was responsible for significant advances in the simulation of the Madden–Julian Oscillation (MJO) in the ECMWF model. However, the application of traditional MJO diagnostics were not adequate to understand why changing the ...

The observed convective adjustment time (CAT) associated with Madden–Julian Oscillation (MJO) precipitation is found to vary significantly in space. Here, we investigate the effect of different spatial distributions of CAT on MJO precipitation based on the frictional coupled dynamics moisture (FCDM) model. The results show that a large value of CAT tends to decrease the frequency and growth rat...