Juli 2025:
Neue Veröffentlichung:
Tian, Q., J.-Y. Yu, H. C. Nnamchi, T. Li, J. Li, L. Zhang, X. Li (2025). Unraveling the mystery of recent shortened response time of ENSO to Atlantic forcing. Nature Communications. 16, 5884. https://doi.org/10.1038/s41467-025-61130-4
Abstract:
The El Niño-Southern Oscillation (ENSO) is known to respond to tropical Atlantic (TA) sea surface temperature (SST) forcing. However, the response time of ENSO to the TA SST forcing is not stationary but varies over decades, the reasons for which remain poorly understood. Here we show that decadal changes in ENSO’s response time to TA SST forcing are primarily influenced by the south-north shift of the dominant mode of TA SST variability itself. Before the mid-1980s, the southward-shifted TA mode prolongs the response time to ~20 months through an eastward-propagating mid-latitude teleconnection. In contrast, when the TA mode shifts northward after the mid-1980s, the response time decreases to 6–9 months via a faster westward-propagating subtropical teleconnection. Our findings underscore the importance of considering the meridional shift of the TA mode when understanding the impacts of the TA SST variability on ENSO, which has profound implications for ENSO forecasting.
Schematic diagram illustrating the physical mechanisms driving the changes in the tropical Atlantic (TA)−El Niño-Southern Oscillation (ENSO) relationship.
During 1960–1984 (P1), when spring-to-summer TA mode moves southward, the South Tropical Atlantic (STA) warming can force South Pacific Oscillation (SPO)-like atmospheric circulation anomalies by an eastward-propagating Mid-latitude Rossby wave, which can then induce a South Pacific Meridional Mode (SPMM)-like sea surface temperature (SST) footprint during the winter of the first year. The SPMM interacts with the trade winds and extends negative SST anomalies equatorward into the equatorial Pacific through the wind–evaporation–SST (WES) feedback, leading to an eastern Pacific (EP)-type La Niña event over the equatorial Pacific during the winter of the second year. During 1990–2014 (P2), when spring-to-summer TA mode moves northward, the North Tropical Atlantic (NTA) warming can quickly initiate a central Pacific (CP)-type La Niña event through a westward-propagating subtropical Rossby wave during the winter of the first year.
April 2025:
Neue Veröffentlichung:
Nnamchi, H.C., Latif, M. Predictable equatorial Atlantic variability from atmospheric convection-ocean coupling. npj Clim Atmos Sci 8, 149 (2025). https://doi.org/10.1038/s41612-025-01041-9
Abstract:
The Atlantic Niño exerts profound impacts on regional and global atmospheric circulation and climate, and on equatorial Atlantic biogeochemistry and ecosystems. However, the mode’s prediction remains a challenge which has been partly attributed to weak atmosphere-ocean coupling in the region. Here we introduce a framework that enhances the detection of the coupling between meridional migrations of atmospheric deep convection and zonal thermocline feedback. This approach reveals high predictive skill in a 196-member seasonal prediction ensemble, demonstrating robust predictability at 1–5-month forecast initialization lead times. The coupled mode is strongly correlated with land-precipitation variability across the tropics. The predictive skill largely originates in the Atlantic Ocean and is uncorrelated with El Niño Southern Oscillation in the Pacific, the leading mode of interannual climate variability globally. These skillful predictions raise hopes for enabled action in advance to avoid the most severe societal impacts in the affected countries.
The leading zonal-meridional coupled variability mode in the equatorial Atlantic 1982–2004.
a–c Meridional precipitation anomalies regressed on the SST-PC1 (color-scale), the contours show the SST anomalies regressed on the precipitation-PC1; d–f Zonal-SST anomalies regressed on the precipitation-PC1 (color-scale), the contours show the precipitation anomalies regressed on the SST-PC1; g–i Zonal SSH anomalies regressed on the precipitation-PC1 (color-scale), the contours show the SSH anomalies regressed on the SST-PC1. j–l Normalized precipitation-PC1 (dashed, blue) and SST-PC1 (solid, red). Left–right columns: observations, CMIP5, and CMIP6 ensembles, respectively. In panels a–i, the stipples denote statistical significance at the 95% confidence level; the contour intervals are 0.1 K for SST, 0.3 mm/day for precipitation, and 10-2 m for the SSH anomalies.
April 2025:
Neue Veröffentlichung:
Christian Baatz, Lukas Tank, Lena-Katharina Bednarz, Miranda Boettcher, Teresa Maria Morganti, Lieske Voget- Kleschin, Tony Cabus, Erik van Doorn, Tabea Dorndorf, Felix Havermann, Wanda Holzhüter, David Peter Keller, Matthias Kreuzburg, Nele Matz-Lück, Nadine Mengis, Christine Merk, Yiannis Moustakis, Julia Pongratz, Hendrikje Wehnert, Wanxuan Yao and Gregor Rehder (2025): "A holistic assessment framework for marine carbon dioxide removal options." Environmental Research Letters, DOI: 10.1088/1748-9326/adc93f
Abstract:
Marine Carbon Dioxide Removal (mCDR) options could potentially play an important role in future CDR policy portfolios. They include, for example, ocean alkalinity enhancement, blue carbon projects such as mangrove cultivation, as well as sub-seabed storage of captured atmospheric CO2. We present a novel assessment framework designed for mCDR options. The framework provides important conceptual advancements to existing frameworks currently used to assess climate options: It clearly distinguishes between and allows for the assessment of both the feasibility and desirability of mCDR options, it makes explicit the evaluative standards upon which the assessment is based and it separates the descriptive listing of information from the evaluation of said information. The assessment framework aims to advance the debate on what role mCDR can and should play in responding to the climate crisis by providing a tool for both policymakers and stakeholders to assess mCDR options in a transparent and comprehensive way.
April 2025:
Neue Veröffentlichung:
Tank, L., Voget-Kleschin, L., Garschagen, M., Boettcher, M., Mengis, N., Holland-Cunz, A., Rehder, G., and Baatz, C. (2025) "Distinguish between feasibility and desirability when assessing climate response options." npj Climate Action 4, 34. https://doi.org/10.1038/s44168-025-00237-2
Abstract:
The current literature on assessing climate change response options does not sufficiently distinguish between assessing options in terms of their feasibility and in terms of their desirability. One example of this is the IPCC feasibility assessment framework. We argue that assessments of climate response options should indeed cover questions of desirability, but they should do so explicitly. Transparency about underlying normative standards is the key to a productive desirability assessment.
