Open Access Digital Repository of Ministry of Earth Sciences, Government of India

Links between tropical SST anomalies and precursory signals associated with the interannual variability of Asian summer monsoon

Thomas, B and Kasture, SV and Satyan, V (2000) Links between tropical SST anomalies and precursory signals associated with the interannual variability of Asian summer monsoon. Meteorology and Atmospheric Physics, 75 (1-2). pp. 39-49.

Full text not available from this repository. (Request a copy)

Abstract

The interannual variability of broad-scale Asian summer monsoon was studied using a general circulation model (GCM) and NCEP (National Center for Environmental Prediction) data set during 1979-95. In the GCM experiment, the main emphasis was given to isolate the individual role of surface boundary conditions on the existence of winter-spring time circulation anomalies associated with the interannual variability of Asian summer monsoon. In order to understand the role of sea-surface temperatures (SSTs) alone on the existence of precursory signals, we have conducted 17 years numerical integration with a GCM forced with the real-time monthly averaged SSTs of 1979 to 1995. In this experiment, among the many surface boundary conditions only SSTs are varying interannually. The composite circulation anomalies simulated by the GCM have good resemblance with the NCEP circulation anomalies over subtropical Asia. This suggests that the root cause of the existence of winter-spring time circulation anomalies associated with the interannual variability of Asian summer monsoon is the interannual variability of SST. Empirical Orthogonal Functions (EOFs) of 200-mb winds and OLR were constructed to study the dynamic coupling between SST anomalies and winter-spring time circulation anomalies. It is found that the convective heating anomalies associated with SST anomalies and stationary eddies undergo systematic and coherent inter-annual variations prior to summer season. We have identified Matsuno-Gill type mode in the velocity potential and stream function fields. This suggests the existence of dynamic links between the SST anomalies and the precursory signals of Asian summer monsoon.

Item Type: Article
Additional Information: Copyright of this article belongs to Springer
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 14 Mar 2015 18:35
Last Modified: 14 Mar 2015 18:35
URI: http://moeseprints.incois.gov.in/id/eprint/1592

Actions (login required)

View Item View Item