Advanced Search
ZHANG Dongling, LU Xu, and ZHANG Ming. 2019: Analysis of Ocean-Atmosphere Circulation Modes Associated withTwo Types of ENSO in January. Chinese Journal of Atmospheric Sciences, 43(4): 741-758. DOI: 10.3878/j.issn.1006-9895.1810.17229
Citation: ZHANG Dongling, LU Xu, and ZHANG Ming. 2019: Analysis of Ocean-Atmosphere Circulation Modes Associated withTwo Types of ENSO in January. Chinese Journal of Atmospheric Sciences, 43(4): 741-758. DOI: 10.3878/j.issn.1006-9895.1810.17229

Analysis of Ocean-Atmosphere Circulation Modes Associated withTwo Types of ENSO in January

  • In this paper, combined complex Empirical Orthogonal Function(CEOF)analysis is applied to the atmospheric wind and ocean flow fields in January from 1950 to 2001 to understand the coupled ocean-atmosphere circulation associated with two types of El Niño-Southern Oscillation(ENSO)in January. The results are as follows. The first and second modes respectively correspond to the Eastern Pacific type of ENSO (EP-ENSO) and the Central Pacific type of ENSO (CP-ENSO). The former type of ENSO corresponds to sea surface temperature (SST) anomalies in the eastern and central equatorial Pacific, and the eastern anomaly is stronger; the latter corresponds to SST anomaly only in the central equatorial Pacific. Their time coefficients are closely related to ENSO. Thereby, they can be named as EP-ENSO mode and CP-ENSO mode regarding wind-current fields, respectively. The EP-ENSO mode has distinct interannual and interdecadal variations with periods of 3 to 6 and 13 to 14 years. The CP-ENSO mode has distinct interannual and interdecadal variations with periods of 7, 12 and 17 years. The 13-year period is similar to the NPGO(North Pacific Gyre Oscillation)period of winter climate mode in the North Pacific. During the Eastern and Central Pacific type of El Niño, the ascending branch of the Walker Circulation shifts eastward from Indonesia to the western or central equatorial Pacific, and the intensity weakens; the southern and northern branches of Hadley Circulation are respectively located to the east of and near the international date line, and the intensity enhances, which causes the subtropical high to become stronger; along the coast of South America near 5°S, there are anomalies of updraft and downdraft. For the two types of ENSO modes, westerly anomalies and wave packet solutions of Kelvin wave and Rossby wave are coupled near the central equatorial Pacific. Sea temperature kinetic anomaly has a negative feedback on the atmospheric circulation, which is favorable for the maintenance and stability of ENSO.
  • loading

Catalog

    Turn off MathJax
    Article Contents

    /

    DownLoad:  Full-Size Img  PowerPoint
    Return
    Return