Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Neogene South Asian monsoon rainfall and wind histories diverged due to topographic effects

Abstract

The drivers of the evolution of the South Asian Monsoon remain widely debated. An intensification of monsoonal rainfall recorded in terrestrial and marine sediment archives from the earliest Miocene (23–20 million years ago (Ma)) is generally attributed to Himalayan uplift. However, Indian Ocean palaeorecords place the onset of a strong monsoon around 13 Ma, linked to strengthening of the southwesterly winds of the Somali Jet that also force Arabian Sea upwelling. Here we reconcile these divergent records using Earth system model simulations to evaluate the interactions between palaeogeography and ocean–atmosphere dynamics. We show that factors forcing the South Asian Monsoon circulation versus rainfall are decoupled and diachronous. Himalayan and Tibetan Plateau topography predominantly controlled early Miocene rainfall patterns, with limited impact on ocean–atmosphere circulation. The uplift of the East African and Middle Eastern topography played a pivotal role in the establishment of the modern Somali Jet structure above the western Indian Ocean, while strong upwelling initiated as a direct consequence of the emergence of the Arabian Peninsula and the onset of modern-like atmospheric circulation. Our results emphasize that although elevated rainfall seasonality was probably a persistent feature since the India–Asia collision in the Paleogene, modern-like monsoonal atmospheric circulation only emerged in the late Neogene.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Western Indian Ocean palaeogeographic reconstructions.
Fig. 2: Change in Arabian Sea productivity between the EM and LM.
Fig. 3: Changes in ocean–atmosphere dynamics in response to Miocene palaeogeographic evolution.
Fig. 4: SAM circulation and rainfall in sensitivity experiments.

Similar content being viewed by others

Data availability

All model outputs used in this study are available as a NetCDF via Zenodo at https://doi.org/10.5281/zenodo.5727042 (ref. 84). The EM palaeogeographic reconstructions38 are also available on the Paleoenvironment map website (https://map.paleoenvironment.eu). The repository also contains palaeogeography grids used for the simulations.

Code availability

LMDZ, XIOS, NEMO and ORCHIDEE are released under the terms of the CeCILL license. OASIS-MCT is released under the terms of the Lesser GNU General Public License (LGPL). IPSL-CM5A2 source code is publicly available through svn, with the following commands line: svn co http://forge.ipsl.jussieu.fr/igcmg/svn/modipsl/branches/publications/IPSLCM5A2.1_11192019; cd modipsl/util; ./model IPSLCM5A2.1. The mod.def file provides information regarding the different revisions used, namely: NEMOGCM branch nemo_v3_6_STABLE revision 6665; XIOS2 branchs/xios-2.5 revision 1763; IOIPSL/src svn tags/v2_2_2; LMDZ5 branches/IPSLCM5A2.1 rev 3591; branches/publications/ORCHIDEE_IPSLCM5A2.1.r5307 rev 6336; OASIS3-MCT 2.0_branch (rev 4775 IPSL server). The login/password combination requested at first use to download the ORCHIDEE component is anonymous/anonymous. We recommend that you refer to the project website (http://forge.ipsl.jussieu.fr/igcmg_doc/wiki/Doc/Config/IPSLCM5A2) to install and compile the environment correctly. Adaptations of the PISCES model used in the study are archived in Zenodo at https://doi.org/10.5281/zenodo.5727042, along with information on how to include the updates in the reference code of PISCES. Analysis and graphics from this paper have been produced using open-source tools. PyFerret is a product of the NOAA’s Pacific Marine Environmental Laboratory (information is available at http://ferret.pmel.noaa.gov/Ferret/). Information on NCL85 is available at https://www.ncl.ucar.edu. Information on the Generic Mapping Tool86 is available at https://www.generic-mapping-tools.org.

References

  1. Raymo, M. E. & Ruddiman, W. F. Tectonic forcing of late Cenozoic climate. Nature 359, 117–122 (1992).

    Article  Google Scholar 

  2. Kroon, D., Steens, T. N. F. & Troelstra, S. R. Onset of monsoon related upwelling in the Western Arabian Sea as revealed by planktonic foraminifers. Proc. ODP Sci. Results 117, 257–263 (1991).

    Google Scholar 

  3. Licht, A. et al. Asian monsoons in a late Eocene greenhouse world. Nature 513, 501–506 (2014).

    Article  Google Scholar 

  4. Bhatia, H. et al. Late Cretaceous–Paleogene Indian monsoon climate vis-à-vis movement of the Indian plate, and the birth of the South Asian Monsoon. Gondwana Res. 93, 89–100 (2021).

    Article  Google Scholar 

  5. Clift, P. D. & Webb, A. A. G. History of the Asian monsoon and its interactions with solid earth tectonics in Cenozoic South Asia. Geol. Soc. Lond. Spec. Publ. 483, 875–880 (2019).

  6. Gupta, A. K., Yuvaraja, A., Prakasam, M., Clemens, S. C. & Velu, A. Evolution of the South Asian monsoon wind system since the late Middle Miocene. Palaeogeogr. Palaeoclimatol. Palaeoecol. 438, 160–167 (2015).

    Article  Google Scholar 

  7. Bialik, O. M. et al. Monsoons, upwelling, and the deoxygenation of the Northwestern Indian ocean in response to middle to late miocene global climatic shifts. Paleoceanogr. Paleoclimatol. 35, e2019PA003762 (2020).

    Article  Google Scholar 

  8. Nigrini, C. Composition and biostratigraphy of radiolarian assemblages from an area of upwelling (northwestern Arabian Sea, lag 117). Proc. ODP Sci. Results 117, 89–126 (1991).

    Google Scholar 

  9. Huang, Y., Clemens, S. C., Liu, W., Wang, Y. & Prell, W. L. Large-scale hydrological change drove the late Miocene C4 plant expansion in the Himalayan foreland and Arabian peninsula. Geology 35, 531–534 (2007).

    Article  Google Scholar 

  10. Zhuang, G., Pagani, M. & Zhang, Y. G. Monsoonal upwelling in the western Arabian Sea since the middle Miocene. Geology 45, 655–658 (2017).

    Article  Google Scholar 

  11. Betzler, C. et al. The abrupt onset of the modern South Asian Monsoon winds. Sci. Rep. 6, 29838 (2016).

    Article  Google Scholar 

  12. Gébelin, A. et al. The miocene elevation of Mount Everest. Geology 41, 799–802 (2013).

    Article  Google Scholar 

  13. Ding, L. et al. Quantifying the rise of the Himalaya orogen and implications for the South Asian Monsoon. Geology 45, 215–218 (2017).

    Article  Google Scholar 

  14. Prell, W. L. & Kutzbach, J. E. Sensitivity of the Indian monsoon to forcing parameters and implications for its evolution. Nature 360, 647–652 (1992).

    Article  Google Scholar 

  15. Tada, R., Zheng, H. & Clift, P. D. Evolution and variability of the Asian monsoon and its potential linkage with uplift of the Himalaya and Tibetan plateau. Prog. Earth Planet. Sci. 3, 4 (2016).

    Article  Google Scholar 

  16. Molnar, P., Boos, W. R. & Battisti, D. S. Orographic controls on climate and paleoclimate of Asia: thermal and mechanical roles for the tibetan plateau. Annu. Rev. Earth Planet. Sci. 38, 77–102 (2010).

    Article  Google Scholar 

  17. Acosta, R. P. & Huber, M. Competing topographic mechanisms for the Summer Indo-Asian Monsoon. Geophys. Res. Lett. 47, e2019GL085112 (2020).

    Article  Google Scholar 

  18. Thomson, J. R. et al. Tectonic and climatic drivers of Asian monsoon evolution. Nat. Commun. 12, 4022 (2021).

    Article  Google Scholar 

  19. Chakraborty, A., Nanjundiah, R. S. & Srinivasan, J. Impact of African orography and the Indian summer monsoon on the low-level Somali jet. Int. J. Clim. 29, 983–992 (2009).

    Article  Google Scholar 

  20. Wei, H.-H. & Bordoni, S. On the role of the African topography in the South Asian monsoon. J. Atmos. Sci. 73, 3197–3212 (2016).

    Article  Google Scholar 

  21. Tang, H., Micheels, A., Eronen, J. T., Ahrens, B. & Fortelius, M. Asynchronous responses of East Asian and Indian summer monsoons to mountain uplift shown by regional climate modelling experiments. Clim. Dynam. 40, 1531–1549 (2013).

    Article  Google Scholar 

  22. Zhang, R., Jiang, D., Zhang, Z. & Yu, E. The impact of regional uplift of the Tibetan Plateau on the Asian monsoon climate. Palaeogeogr. Palaeoclimatol. Palaeoecol. 417, 137–150 (2015).

    Article  Google Scholar 

  23. Zhang, Z. et al. Aridification of the Sahara desert caused by Tethys Sea shrinkage during the Late Miocene. Nature 513, 401–404 (2014).

    Article  Google Scholar 

  24. Fluteau, F., Ramstein, G. & Besse, J. Simulating the evolution of the Asian and African monsoons during the past 30 Myr using an atmospheric general circulation model. J. Geophys. Res. Atmos. 104, 11995–12018 (1999).

    Article  Google Scholar 

  25. Sepulchre, P. et al. IPSL-CM5A2–an earth system model designed for multi-millennial climate simulations. Geosci. Model Dev. 13, 3011–3053 (2020).

    Article  Google Scholar 

  26. Aumont, O., Ethé, C., Tagliabue, A., Bopp, L. & Gehlen, M. PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies. Geosci. Model Dev. 8, 2465–2513 (2015).

    Article  Google Scholar 

  27. Koné, V., Aumont, O., Lévy, M. & Resplandy, L. in Indian Ocean Biogeochemical Processes and Ecological Variability Vol. 185 (eds Wiggert, J. D. et al.) 147–166 (American Geophysical Union, 2009).

  28. Webster, P. J. & Yang, S. Monsoon and ENSO: selectively interactive systems. Q. J. R. Meteorol. Soc. 118, 877–926 (1992).

    Article  Google Scholar 

  29. Tardif, D. et al. The origin of Asian monsoons: a modelling perspective. Clim. Past 16, 847–865 (2020).

    Article  Google Scholar 

  30. McQuarrie, N. & van Hinsbergen, D. J. Retrodeforming the Arabia-Eurasia collision zone: age of collision versus magnitude of continental subduction. Geology 41, 315–318 (2013).

    Article  Google Scholar 

  31. Miller, K. G. et al. Cenozoic sea-level and cryospheric evolution from deep-sea geochemical and continental margin records. Sci. Adv. 6, eaaz1346 (2020).

    Article  Google Scholar 

  32. Guo, Z. et al. Onset of Asian desertification by 22 Myr ago inferred from loess deposits in China. Nature 416, 159–163 (2002).

    Article  Google Scholar 

  33. Sun, X. & Wang, P. How old is the Asian monsoon system?—Palaeobotanical records from China. Palaeogeogr. Palaeoclimatol. Palaeoecol. 222, 181–222 (2005).

    Article  Google Scholar 

  34. Farnsworth, A. et al. Past East Asian monsoon evolution controlled by paleogeography, not CO2. Sci. Adv. 5, eaax1697 (2019).

    Article  Google Scholar 

  35. Spicer, R. et al. Paleogene monsoons across India and South China: drivers of biotic change. Gondwana Res. 49, 350–363 (2017).

    Article  Google Scholar 

  36. Clift, P. D. et al. Correlation of Himalayan exhumation rates and Asian monsoon intensity. Nat. Geosci. 1, 875–880 (2008).

    Article  Google Scholar 

  37. Dowsett, H. et al. The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction. Clim. Past 12, 1519–1538 (2016).

    Article  Google Scholar 

  38. Poblete, F. et al. Towards interactive global paleogeographic maps, new reconstructions at 60, 40 and 20 Ma. Earth Sci. Rev 214, 103508 (2021).

    Article  Google Scholar 

  39. Dufresne, J. L. et al. Climate change projections using the IPSL-CM5 earth system model: from CMIP3 to CMIP5. Clim. Dynam. 40, 2123–2165 (2013).

    Article  Google Scholar 

  40. Hourdin, F. et al. Impact of the LMDz atmospheric grid configuration on the climate and sensitivity of the IPSL-CM5A coupled model. Clim. Dynam. 40, 2167–2192 (2013).

    Article  Google Scholar 

  41. Krinner, G. et al. A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system. Glob. Biogeochem. Cycles 19, GB1015 (2005).

    Article  Google Scholar 

  42. Madec, G. NEMO Ocean Engine Scientific Notes of Climate Modelling Center No. 27 (IPSL, 2016).

  43. Fichefet, T. & Maqueda, M. M. Sensitivity of a global sea ice model to the treatment of ice thermodynamics and dynamics. J. Geophys. Res. Oceans 102, 12609–12646 (1997).

    Article  Google Scholar 

  44. Laugie, M. et al. Stripping back the modern to reveal the Cenomanian–Turonian climate and temperature gradient underneath. Clim. Past 16, 953–971 (2020).

    Article  Google Scholar 

  45. Toumoulin, A. et al. Quantifying the effect of the Drake passage opening on the Eocene ocean. Paleoceanogr. Paleoclimatol. 35, e2020PA003889 (2020).

    Article  Google Scholar 

  46. Haywood, A. M. et al. A return to large-scale features of Pliocene climate: the Pliocene Model Intercomparison Project Phase 2. Clim. Past 6, 2095–2123 (2020).

    Article  Google Scholar 

  47. Burls, N. B. et al. Simulating Miocene warmth: insights from an opportunistic multi model ensemble 1 (MioMIP1). Paleoceanogr. Paleoclimatol. 36, e2020PA004054 (2021).

    Article  Google Scholar 

  48. Lunt, D. J. et al. DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data. Clim. Past 17, 203–227 (2021).

    Article  Google Scholar 

  49. Bopp, L. et al. Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models. Biogeosciences 10, 6225–6245 (2013).

    Article  Google Scholar 

  50. Ladant, J.-B., Donnadieu, Y., Bopp, L., Lear, C. H. & Wilson, P. A. Meridional contrasts in productivity changes driven by the opening of Drake passage. Paleoceanogr. Paleoclimatol. 33, 302–317 (2018).

    Article  Google Scholar 

  51. Bopp, L., Kohfeld, K. E., Le Quéré, C. & Aumont, O. Dust impact on marine biota and atmospheric CO2 during glacial periods. Paleoceanography 18, 1046 (2003).

    Article  Google Scholar 

  52. Tagliabue, A. et al. Quantifying the roles of ocean circulation and biogeochemistry in governing ocean carbon-13 and atmospheric carbon dioxide at the last glacial maximum. Clim. Past 5, 695–706 (2009).

    Article  Google Scholar 

  53. Bopp, L., Resplandy, L., Untersee, A., Le Mezo, P. & Kageyama, M. Ocean (de)oxygenation from the Last Glacial Maximum to the twenty-first century: insights from Earth System models. Phil. Trans. R. Soc. A 375, 20160323 (2017).

    Article  Google Scholar 

  54. Le Mézo, P., Beaufort, L., Bopp, L., Braconnot, P. & Kageyama, M. From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates. Clim. Past 13, 759 (2017).

    Article  Google Scholar 

  55. Resplandy, L. et al. Contribution of mesoscale processes to nutrient budgets in the Arabian sea. J. Geophys. Res. Oceans 116, C11007 (2011).

    Article  Google Scholar 

  56. Laugié, M. et al. Exploring the impact of Cenomanian paleogeography and marine gateways on oceanic oxygen. Paleoceanogr. Paleoclimatol. 36, e2020PA004202 (2021).

    Article  Google Scholar 

  57. Ludwig, W., Probst, J.-L. & Kempe, S. Predicting the oceanic input of organic carbon by continental erosion. Glob. Biogeochem. Cycles 10, 23–41 (1996).

    Article  Google Scholar 

  58. Mayorga, E. et al. Global nutrient export from watersheds 2 (NEWS 2): model development and implementation. Environ. Model. Softw. 25, 837–853 (2010).

    Article  Google Scholar 

  59. Torsvik, T. H., Müller, R. D., Van der Voo, R., Steinberger, B. & Gaina, C. Global plate motion frames: toward a unified model. Rev. Geophys. 46, RG3004 (2008).

    Article  Google Scholar 

  60. Hall, R. in Biotic Evolution Environmental Change in Southeast Asia (eds Gower, D. J. et al.) 32–78 (Cambridge Univ. Press, 2012).

  61. Rögl, F. Mediterranean and Paratethys. Facts and hypotheses of an Oligocene to Miocene paleogeography (short overview). Geol. Carpath. 50, 339–349 (1999).

    Google Scholar 

  62. Fang, X. et al. Revised chronology of central Tibet uplift (Lunpola basin). Sci. Adv. 6, eaba7298 (2020).

  63. Botsyun, S. et al. Revised paleoaltimetry data show low Tibetan plateau elevation during the Eocene. Science 363, eaaq1436 (2019).

    Article  Google Scholar 

  64. Quade, J., Breecker, D. O., Daëron, M. & Eiler, J. The paleoaltimetry of Tibet: an isotopic perspective. Am. J. Sci. 311, 77–115 (2011).

    Article  Google Scholar 

  65. Wang, W. et al. Expansion of the Tibetan plateau during the Neogene. Nat. Commun. 8, 15887 (2017).

    Article  Google Scholar 

  66. Webb, A. A. G. et al. The Himalaya in 3D: slab dynamics controlled mountain building and monsoon intensification. Lithosphere 9, 637–651 (2017).

    Google Scholar 

  67. Vicente de Gouveia, S. et al. Evidence of hotspot paths below Arabia and the Horn of Africa and consequences on the Red Sea opening. Earth Planet. Sci. Lett. 487, 210–220 (2018).

    Article  Google Scholar 

  68. Couvreur, T. L. P. et al. Tectonic, climate and the diversification of the tropical African terrestrial flora and fauna. Bio. Rev. 96, 16–51 (2020).

    Article  Google Scholar 

  69. Sembroni et al. Long-term, deep-mantle support of the Ethiopia-Yemen Plateau. Tectonics 35, 469–488 (2016).

    Article  Google Scholar 

  70. Faccenna, C. et al. Role of dynamic topography in sustaining the Nile River over 30 million years. Nat. Geosci. 12, 1012–1017 (2019).

    Article  Google Scholar 

  71. Pik, R., Marty, B., Carignan, J., Yirgu, G. & Ayalew, T. Timing of East African Rift development in southern Ethiopia; implication for mantle plume activity and evolution of topography. Geology 36, 167–170 (2008).

    Article  Google Scholar 

  72. Wichura, H., Bousquet, R., Oberhänsli, R., Strecker, M. R. & Trauth, M. H. Evidence for middle Miocene uplfit of East African Plateau. Geology 38, 543–546 (2010).

    Article  Google Scholar 

  73. François, T. et al. Cenozoic exhumation of the internal Zagros: first constraints from low-temperature thermochronology and implications for the build-up of the Iranian plateau. Lithos 206–207, 100–112 (2014).

    Article  Google Scholar 

  74. Austermann, J. & Iaffaldano, G. The role of the zagros orogeny in slowing down Arabia-Zurasia convergence since 5 Ma. Tectonics 32, 351–363 (2013).

    Article  Google Scholar 

  75. Bialik, O. M., Frank, M., Betzler, C., Zammit, R. & Waldmann, N. D. Two-step closure of the Miocene Indian Ocean gateway to the Mediterranean. Sci. Reports 9, 8842 (2019).

    Google Scholar 

  76. Xie, S. P. et al. Role of narrow mountains in large-scale organization of Asian monsoon convection. J. Clim. 19, 3420–3429 (2006).

    Article  Google Scholar 

  77. Sijikumar, S., John, L. & Manjusha, K. Sensitivity study on the role of Western Ghats in simulating the Asian summer monsoon characteristics. Meteorol. Atmos. Phys. 120, 53–60 (2013).

    Article  Google Scholar 

  78. Leutert, T. J., Auderset, A., Martínez-García, A., Modestou, S. & Meckler, A. N. Coupled southern ocean cooling and Antarctic ice sheet expansion during the middle Miocene. Nat. Geosci. 13, 634–639 (2020).

    Article  Google Scholar 

  79. Gasson, E., DeConto, R. M., Pollard, D. & Levy, R. H. Dynamic Antarctic ice sheet during the early to mid-Miocene. Proc. Natl Acad. Sci. USA 113, 3459–3464 (2016).

    Article  Google Scholar 

  80. Foster, G. L., Royer, D. L. & Lunt, D. J. Future climate forcing potentially without precedent in the last 420 million years. Nat. Commun. 8, 14845 (2017).

    Article  Google Scholar 

  81. Lunt, D. J. et al. The DeepMIP contribution to PMIP4: experimental design for model simulations of the EECO, PETM, and pre-PETM (version 1.0). Geosci. Model. Dev. 10, 889–901 (2017).

    Article  Google Scholar 

  82. Séférian, R. et al. Inconsistent strategies to spin up models in CMIP5: implications for ocean biogeochemical model performance assessment. Geosci. Model. Dev. 9, 1827–1851 (2016).

    Article  Google Scholar 

  83. Crameri, F., Shephard, G. E. & Heron, P. J. The misuse of colour in science communication. Nat. Commun. 11, 5444 (2020).

    Article  Google Scholar 

  84. Sarr, A.-C. Evolution of Indian Ocean Paleoceanography and South-East Asian Climate during the Miocene in response to change in regional topography [Data set]. Zenodo https://doi.org/10.5281/zenodo.5727042 (2022).

  85. NCAR Command Language v.6.3.0 (UCAR/NCAR/CISL/TDD, 2015); https://doi.org/10.5065/D6WD3XH5

  86. Wessel, P., Smith, W. H. F., Scharroo, R., Luis, J. & Wobbe, F. Generic Mapping Tools: improved version released. Eos 94, 409–410 (2013).

  87. Herbert, T. D. et al. Late Miocene global cooling and the rise of modern ecosystems. Nat. Geosci. 9, 843–847 (2016).

    Article  Google Scholar 

  88. Huffman, G. J., Adler, R. F., Bolvin, D. T. & Gu, G. Improving the global precipitation record: GPCP version 2.1. Geophys. Res. Lett. 36, L17808 (2009).

    Article  Google Scholar 

Download references

Acknowledgements

We thank the CEA/CCRT for providing access to the HPC resources of TGCC under allocation numbers 2018-A0030102212, 2019-A0050102212 and 2020-A0090102212 made by GENCI and the French ANR project AMOR (ANR-16-CE31-0020) (Y.D.) for providing funding for this work. Coloured figures in this Article were made with perceptually uniform, colour-vision-deficiency-friendly scientific colour maps, developed and distributed by F. Crameri83 (https://www.fabiocrameri.ch/colourmaps/). We thank C. Ethé, L. Bopp and O. Aumont for technical help with adapting PISCES for deep-time configurations.

Author information

Authors and Affiliations

Authors

Contributions

A.-C.S. and Y.D. designed the study and ran the simulations. F.F. provided updated palaeogeographies and expertise on palaeogeographic evolution. J.-B.L. and M.L. developed and ran the tests for the runoff-adapted version of PISCES and helped with the set-up of PISCES simulations. C.T.B. helped to compile and synthesize palaeoceanographic records. A.-C.S., Y.D., C.T.B., A.L. and J.-B.L. wrote the manuscript. G.D.-N., F.F. and D.T. contributed substantial comments and revisions.

Corresponding author

Correspondence to Anta-Clarisse Sarr.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Geoscience thanks Guangsheng Zhuang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: James Super, in collaboration with the Nature Geoscience team.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Paleogeographic reconstruction used in the reference simulations.

a) late Miocene (LM) and b) early Miocene (EM) simulations. Initial bathymetry is more detailed in LM than in EM paleogeography, but the model resolution (2° by 2°) mitigates the difference by smoothing small variations.

Extended Data Fig. 2 Simulation equilibrium and zonal mean temperature gradient.

a) Global ocean temperature evolution at the sea surface, in intermediate (1,000 m) and deep waters (4,000 m) for late Miocene (LM) and early Miocene (EM) simulations, and sensitivity experiments. Zonal mean SST gradient for EM (b) and LM (c) simulations compared to available proxy estimation. Bold line indicates mean annual SST, dashed line depicts minimum and maximum value for each latitude. Temperature reconstruction are from ref. 47, based on compilation by ref. 87 and additional information on the compilation can be found in ref. 47.

Extended Data Fig. 3 Western Indian ocean response to Miocene paleogeographic evolution.

Top: Sea surface temperatures (°C) averaged over boreal summer (JAS); Bottom: Mixed layer depth average during boreal summer (JAS). (a)(d) late Miocene (LM) and (b)(e) early Miocene (EM) and (c)(f) LM-NoEAP simulations (See Extended Data Table 1 and Extended Data Fig. 4). LM-NoEAP is a simulation without the Eastern Arabian Peninsula (EAP), designed to show the influence of Arabian Peninsula immersion on the Somali Jet structure in a LM configuration.

Extended Data Fig. 4 Paleogeographic changes used in the sensitivity experiments.

Paleogeography surrounding the Indian Ocean in a) the late Miocene (LM) and e) the early Miocene (EM) simulations. Change in paleogeography between sensitivity experiments and the reference simulation (LM and EM); b) LM-NoAIO (change in Anatolia-Iran orogen (AIO) topography); c) LM-NoEAP (Change in Arabian Peninsula (EAP) land extension) d) LM-NoEAHR (Change in East African Highland (EAH) topography on LM configuration); f) EM-EAH (Change in East African Highland topography on EM configuration); g) EM-HTP (Change in Himalaya and Tibetan Plateau (HTP) topography) and g) EM-Him (Higher than present-day Himalaya). Contours are drawn every 250 meters for EM and LM simulations and every 500 meters for each sensitivity experiment.

Extended Data Fig. 5 Somali Jet response to changes in regional paleogeography.

Low level winds (850 hPa) during boreal summer (JJA) for a) late Miocene (LM) with low CO2 (LM-CO2); b) LM with Expanded Antarctic Ice Sheet (LM-AIS); c) LM with half present-day Anatolia-Iran topography (LM-NoAIO); d) LM with reduced topography in East African Highlands (LM-noEAHR); e) EM with uplifted East African Highlands (EM-EAH); f) EM with fully uplifted HTP region (EM-HTP) and g) EM with higher than present-day Himalaya orography (EM-Him).

Extended Data Fig. 6 Sea level pressure response to Middle Eastern physiographic changes.

Mean summer (JJA) sea level pressure (hPa) for a) late Miocene (LM) with partly submerged Eastern Arabian Peninsula (LM-NoEAP) and b) late Miocene baseline simulation.

Extended Data Fig. 7 Mean summer precipitation response to change in regional physiography.

a) late Miocene (LM), b) LM with half present-day Anatolia-Iran topography (LM-AIO), c) LM with partly submerged Eastern Arabian Peninsula (LM-NoEAP) and reduced topography in the Anatolia-Iran region, d) early Miocene, e) EM with fully uplifted HTP region (EM-HTP), f) EM with higher than present-day Himalaya orography (EM-Him). Dashed square indicates the area over which inland precipitation seasonality index (Main text, Fig. 4) is computed.

Extended Data Fig. 8 Seasonal cycle of precipitation.

Precipitation is averaged over [65E-85E, 0–35N]. a) Global Precipitation Climatology Project (GPCP) data88 and preindustrial simulation25 (Model), b) Low elevation areas (0–1,000 m) and c) high altitude areas (above 1000 m) for early Miocene (EM) and late Miocene (LM) simulations and sensitivity experiments.

Extended Data Fig. 9 Moisture transport response to change in regional physiography.

Late summer vertically integrated moisture transport (JJA) a) late Miocene (LM); b) LM-NoAIO; c) LM-NoEAP, d) early Miocene (EM). Change in vertically integrated moisture transport (JJA) in response to e) change in Anatolia-Iran topography (LM-NoAIO vs. LM); f) emersion of the Eastern Arabian Peninsula (LM-NoEAP vs. LM-NoAIO) and g) paleogeographic evolution between the early and the late Miocene (LM vs. EM).

Extended Data Table 1 Simulations performed with IPSL-CM5A2. See Extended Data Figs. 1 and 4 for paleogeography maps

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Sarr, AC., Donnadieu, Y., Bolton, C.T. et al. Neogene South Asian monsoon rainfall and wind histories diverged due to topographic effects. Nat. Geosci. 15, 314–319 (2022). https://doi.org/10.1038/s41561-022-00919-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41561-022-00919-0

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing