Open AccessLocal and remote atmospheric response to tropical instability waves: A global view from space
Author(s) -
Hashizume Hiroshi,
Xie ShangPing,
Liu W. Timothy,
Takeuchi Kensuke
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd900684
Subject(s) - intertropical convergence zone , equator , sea surface temperature , climatology , geology , anomaly (physics) , tropical atlantic , precipitation , convergence zone , equatorial waves , atmospheric sciences , environmental science , latitude , geography , physics , meteorology , geodesy , condensed matter physics
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 these strong TIWs in 1999. Coherent ocean‐atmosphere patterns emerge in both the Pacific and Atlantic, revealing rich regional characteristics. In the far eastern Pacific, southeasterly trades strengthen (weaken) over positive (negative) SST anomalies, apparently due to enhanced (reduced) mixing with high‐speed winds aloft. In the central Pacific we find evidence that SST‐induced sea level pressure changes also contribute substantially to wind fluctuations. Similar SST‐wind covariability also exists in the Southern Hemisphere along 2°S, but the wind variability induced by unit SST anomaly is much larger than that north of the equator. In the central Pacific where the equatorial front is broad, the northern SST pattern has a large meridional scale and reaches as far north as 6°N. Further to the north in the Intertropical Convergence Zone (ITCZ) where local SST anomalies are small, significant variability is found in clouds and precipitation, which is further correlated with surface wind convergence. In the Atlantic, TIW signals in SST are strongly trapped near the equator, but they induce significant remote response in the ITCZ, which takes a more southern position than its Pacific counterpart and thus more susceptible to TIW influence.