A Comparison of Tropical Mesoscale Convective Systems in El Niño and La Niña

• Published in: Journal of climate Vol. 13; no. 18; pp. 3314 - 3326
• Main Authors: Zolman, Jody L., Zipser, Edward J., Mohr, Karen I.
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 15.09.2000
• Subjects: Atmosphere; Continents; Earth, ocean, space; El Nino; Equatorial regions; Exact sciences and technology; External geophysics; Geophysics. Techniques, methods, instrumentation and models; La Nina; Marine; Meteorology; Ocean currents; Oceans; Precipitation; Rain; Rainy seasons; Southern oscillation; Temperate regions; Tropical regions; Wind; I, Central Pacific; IE, Pacific; Data analysis; Rain; Mesoscale; El Nino; Tropical zone; Convective cloud; Thunderstorm; La Nina
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/1520-0442(2000)013<3314:ACOTMC>2.0.CO;2

Tropical mesoscale convective systems (MCSs) were identified from satellite data using the 85-GHz ice-scattering channel for a La Niña year, and these MCSs were compared with MCSs identified in the same manner for an El Niño year in previous work by Mohr and Zipser. The number, size, and intensity of the MCSs were examined for differences between the years in 18 different regions. There are well-documented patterns of anomalous precipitation related to El Niño and La Niña, and, in general, the MCS distributions between the two years tend to follow these patterns. There were more MCSs in the central Pacific and eastern Pacific in the El Niño year than in the La Niña year, and there were fewer MCSs in the “Maritime Continent.” The area distributions and median intensities of MCSs were found to be similar in each region during the two years. In contrast, the number and total area of MCSs in a region changed between the years. The changes between the years in MCS distributions showed a strong relationship to differences in an independent estimate of rainfall for the two years.