ENSO signatures observed in tropical tropopause layer parameters using long-term COSMIC RO data

Yuei An Liou, Saginela Ravindra Babu

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2 Scopus citations

Abstract

The El Niño Southern Oscillation (ENSO) signatures interpreted in different tropical tropopause layer (TTL) parameters are investigated by using long-term Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC)-1 radio occultation temperature data from July 2006 to March 2019. The TTL parameters include the cold point tropopause height (CPT-H) and corresponding temperature (CPT-T), lapse rate tropopause height (LRT-H) and corresponding temperature (LRT-T), convective outflow level height (COH), and TTL thickness. Results indicate that the warm phase of ENSO is associated with prominent negative CPT-T anomalies, whereas the cold phase of ENSO is associated with positive CPT-T anomalies over the tropical central and eastern Pacific Ocean. Further, correlation analysis is carried out between TTL parameters obtained over the Nino 3.4 region (5°N–5°S, 170°W–120°W) and sea surface temperature Nino 3.4 Index. We found weak positive correlations in CPT-H (0.37) and LRT-H (0.49), and moderate negative correlations in CPT-T (− 0.62), LRT-T (− 0.64), and TTL thickness (− 0.5) with Nino 3.4 Index. Interestingly, a higher correlation of 0.8 is noticed between COH and the Niño 3.4 Index. Furthermore, lag correlation analysis reveals that a 4-month lag is noticed in tropopause heights (CPT-H and LRT-H) and a 2-month lag is evident in tropopause temperatures (CPT-T and LRT-T) with the Niño 3.4 Index. In addition, only 1-month lag is noticed between COH and Niño 3.4 index. With a high correlation and 1-month lag with the Nino 3.4 index, it is concluded that the COH is the most suitable TTL parameter to detect the ENSO signatures among the TTL parameters.

Original languageEnglish
Article number98
JournalGPS Solutions
Volume24
Issue number4
DOIs
StatePublished - 1 Oct 2020

Keywords

  • COSMIC RO
  • Convective tropopause
  • ENSO
  • Tropical tropopause layer

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