The question of why the intertropical convergence zone (ITCZ) is generally north of the equator in the tropical Pacific is addressed. Experiments with an atmospheric general circulation model coupled to idealized representations of the ocean show that the presence of the Andes is enough to lower sea surface temperature (SST) off the west coast of South America through evaporation, thus promotin...

[1] A methodology is presented to linearly correct the tendency of sea surface temperature (SST) anomalies in a coupled model. Using an atmospheric general circulation model (AGCM) coupled to a slab ocean as an example, we demonstrate the effectiveness of the linear correction methodology in improving the model’s skill predicting SST in the tropical Atlantic Ocean during boreal spring. For this...

[1] Column-integrated moist static energy (MSE) budgets were calculated using daily data from three reanalyses (1998–2001) and ISCCP radiative cooling. The MSE export by the circulation was separated into vertical and horizontal MSE advection components in order to examine how observationally-derived vertical motion profiles affect gross moist stability calculations. In a 2000 km-wide region in...

A La Niña took place in the equatorial Pacific in 1999, and strong tropical instability waves (TIWs) developed, causing large meanders of a sea surface temperature (SST) front between the equator and 3◦N. High-resolution satellite measurements are used to describe the variability of SST, surface wind velocity, column-integrated water vapor, cloud liquid water and precipitation associated with t...

The 6-yr (1998–2003) rainfall products from the Tropical Rainfall Measuring Mission (TRMM) are used to quantify the intertropical convergence zone (ITCZ) in the eastern Pacific (defined by longitudinal averages over 90°–130°W) during boreal spring (March–April). The double-ITCZ phenomenon, represented by the occurrence of two maxima with respect to latitude in monthly mean rainfall, is observed...

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this in...

An atmospheric general circulation model (AGCM) is used to examine the role of Indian Ocean sea surface temperature (SST) anomalies in regional climate variability. In particular, the authors focus on the effect of the basinwide warming that occurs during December through May after the mature phase of El Niño. To elucidate the relative importance of local and remote forcing, model solutions wer...

Currently, little is known on how volcanic eruptions impact large-scale climate phenomena such as South American paleo-Intertropical Convergence Zone (ITCZ) position and summer monsoon behavior. In this paper, an analysis of observations and model simulations is employed to assess the influence of large volcanic eruptions on the climate of tropical South America. This problem is first considere...

Based on a widely used satellite precipitation product (TRMM Multi-satellite Precipitation Analysis 3B43), we analyzed the spatiotemporal variability of precipitation over the Pacific Ocean for 1998–2014 at seasonal and interannual timescales, separately, using the conventional empirical orthogonal function (EOF) and investigated the seasonal patterns associated with El Niño–Southern Oscillatio...

[1] Climate models often project an increase of rainfall under global warming over the climatologic wet regions from the global zonal-mean perspective. However, this “rich-get-richer” mechanism is not valid on a basin scale. In this study by analyzing climate change experiment outputs from an idealized atmospheric general circulation model with uniform sea surface warming and the Coupled Model ...