A Surface pCO2 Increasing Hiatus in the Equatorial Pacific Ocean Since 2010. Issue 21 (29th October 2021)

• Record Type: Journal Article
• Authors: Qiu, Shuang; Feng, Yang; Zhang, Yuhong; Qi, Di; Wu, Yingxu; Du, Yan
• Is Part Of: Geophysical research letters. Volume 48:Issue 21(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-29
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL093612
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We used multiple data sets to investigate the decadal and longer time scale variability of sea surface partial pressure of CO2 ( p CO2 ) over the equatorial Pacific Ocean from 1990 to 2019. Unlike the increasing trend in the global oceanic p CO2, both the Niño 3.4 and warm pool regions featured distinct decadal variabilities. A p CO2 increasing stagnation, a hiatus stage, was identified in the Niño 3.4 region from 2010 to 2019. Further analysis demonstrated that low‐frequency p CO2 was negatively correlated with the Interdecadal Pacific Oscillation (IPO) index. Both the 2009/10 and 2015/16 El Niño events and an increasing phase of IPO contributed to this long p CO2 stagnation. Correspondingly, a weaker upwelling was induced in the central and eastern tropical Pacific as the trade winds weakened and thus stagnated the increase in p CO2 in the Niño 3.4 region. Our results imply a significant impact of climate variabilities on sea surface p CO2 in the equatorial Pacific. Plain Language Summary: The equatorial Pacific Ocean is one of the largest natural sources of carbon dioxide (CO2 ) to the atmosphere. It can partially reduce the CO2 absorbed by large areas of the ocean. Here we use a series of data sets to investigate the long‐term variations in the sea surface partial pressure of CO2 over the equatorial Pacific Ocean. Unlike the increasing trend in the global ocean surface p CO2 due to the continuous increase in atmospheric CO2 impacted by human activities, the equatorial Pacific Ocean features significant long‐term variabilities. The p CO2 observations and products that we used support a p CO2 increasing hiatus at the Niño 3.4 region (located in the central and eastern equatorial Pacific Ocean) since 2010. Further analysis found that the hiatus is related to El Niño events and the large‐scale, long period oscillation of the Pacific basin. Our results imply the impact of natural climate variabilities on sea surface p CO2 in this important sea area of the equatorial Pacific Ocean. Key Points: The p CO2 in the equatorial Pacific features a significant long‐term trend and decadal to interdecadal variability The increasing p CO2 in the Niño 3.4 region shows stagnation since 2010 due to El Niño events and the increasing phase of the Interdecadal Pacific Oscillation Pacific natural climate variability mitigates the large CO2 source in the tropical Pacific Ocean