Seasonal climate summary southern hemisphere (spring 2002): the El Niño reaches maturity and dry conditions dominate Australia

Seasonal climate summary southern hemisphere ( winter 2001 ) : near - normal conditions in the tropical Pacific continue

Recent Active Fires under El Niño Conditions in Kalimantan, Indonesia

Analysis of the most recent 10-year periods (2002 to 2011) of MODIS hotspots data (fires) and precipitation in Palangkaraya and Pontianak was carried out to identify seasonal and spatial fire occurrence in Kalimantan under El Niño conditions, and to asses future forest condition in Kalimantan. Most data was tallied every 10-day to analyze seasonal and spatial fire occurrence. Seasonal and spati...

Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections

The El Niño–Southern Oscillation (ENSO) is a major driver of Northern Hemisphere wintertime variability and, generally, the key ingredient used in seasonal forecasts of wintertime surface climate. Modeling studies have recently suggested that ENSO teleconnections might involve both a tropospheric pathway and a stratospheric one. Here, using reanalysis data, we carefully distinguish between the ...

Seasonal Cycle–El Niño Relationship: Validation of Hypotheses

The present paper examines ways in which the seasonal cycle influences the evolution of El Niño in the tropical Pacific. The following hypotheses and associated physical mechanisms are investigated: (i) Hypothesis 1 (H1)—the seasonal warming of the cold tongue early in the calendar year (January–April) favors the initial growth of an event; (ii) hypothesis 2 (H2)—during an event, the warm surfa...

Why might stratospheric sudden warmings occur with similar frequency in El Niño and La Niña winters?

[1] The effect of El Niño-Southern Oscillation (ENSO) on the frequency and character of Northern Hemisphere major mid-winter stratospheric sudden warmings (SSWs) is evaluated using a meteorological reanalysis data set and comprehensive chemistry-climate models. There is an apparent inconsistency between the impact of opposite phases of ENSO on the seasonal mean vortex and on SSWs: El Niño leads...