Sensitivity of the observed and modeled discrepancy in tropical Pacific Sea Surface temperatures to the time interval

Abstract

The time-evolving pattern of ocean surface warming in the Pacific Ocean affects the radiation budget and estimates of global climate sensitivity. Over the historical period, models consistently show a different equatorial Pacific SST warming pattern than observed.Some studies attribute the large discrepancies between the observed and modeled SST trends in the Pacific Ocean, in recent decades, to systemic model biases and their response to greenhouse gas forcing or model biases in the spatial and temporal pattern of multi-decadal variability (e.g., Seager et al, 2019, 2022; Wills et al, 2022). Other studies find that the observed warming pattern can be explained by internal variability (e.g., Olonscheck et al, 2020; Watanabe et al, 2021). Here, we examine whether these analyses of regional temperature changes in the tropical Pacific Ocean are sensitive to the time interval selected to calculate the multi-decadal trends and whether the sensitivity to the time interval can explain the conflicting results of previous studies.Olonscheck, D., Rugenstein, M., & Marotzke, J. (2020). Broad consistency between observed and simulated trends in sea surface temperature patterns. Geophysical Research Letters, 47(10), e2019GL086773.Seager, R., Cane, M., Henderson, N., Lee, D. E., Abernathey, R., & Zhang, H. (2019). Strengthening tropical Pacific zonal sea surface temperature gradient consistent with rising greenhouse gases. Nature Climate Change, 9(7), 517-522.Seager, R., Henderson, N., & Cane, M. (2022). Persistent discrepancies between observed and modeled trends in the tropical Pacific Ocean. Journal of Climate, 1-41.Watanabe, M., Dufresne, J. L., Kosaka, Y., Mauritsen, T., & Tatebe, H. (2021). Enhanced warming constrained by past trends in equatorial Pacific sea surface temperature gradient. Nature Climate Change, 11(1), 33-37.Wills, R. C., Dong, Y., Proistosecu, C., Armour, K. C., & Battisti, D. S. (2022). Systematic Climate Model Biases in the Large‐Scale Patterns of Recent Sea‐Surface Temperature and Sea‐Level Pressure Change. Geophysical Research Letters, 49(17), e2022GL100011.