Article

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

  • Nature Communications 6, Article number: 7423 (2015)
  • doi:10.1038/ncomms8423
  • Download Citation
Received:
Accepted:
Published online:

Abstract

There are large uncertainties looming over the status and fate of the South Asian summer monsoon, with several studies debating whether the monsoon is weakening or strengthening in a changing climate. Our analysis using multiple observed datasets demonstrates a significant weakening trend in summer rainfall during 1901–2012 over the central-east and northern regions of India, along the Ganges-Brahmaputra-Meghna basins and the Himalayan foothills, where agriculture is still largely rain-fed. Earlier studies have suggested an increase in moisture availability and land-sea thermal gradient in the tropics due to anthropogenic warming, favouring an increase in tropical rainfall. Here we show that the land-sea thermal gradient over South Asia has been decreasing, due to rapid warming in the Indian Ocean and a relatively subdued warming over the subcontinent. Using long-term observations and coupled model experiments, we provide compelling evidence that the enhanced Indian Ocean warming potentially weakens the land-sea thermal contrast, dampens the summer monsoon Hadley circulation, and thereby reduces the rainfall over parts of South Asia.

  • Purchase article full text and PDF:

    $32

    Buy now

Additional access options:

Already a subscriber?  Log in  now or  Register  for online access.

References

  1. 1.

    & The Asian Monsoon 651-683 (Springer, 2006).

  2. 2.

    et al. Northern Hemisphere summer monsoon intensified by mega-El Niño/southern oscillation and Atlantic multidecadal oscillation. Proc. Natl Acad. Sci. USA 110, 5347–5352 (2013).

  3. 3.

    , , , & Increasing trend of extreme rain events over India in a warming environment. Science 314, 1442–1445 (2006).

  4. 4.

    et al. Monsoons in a changing world: a regional perspective in a global context. J. Geophys. Res. 118, 3053–3065 (2013).

  5. 5.

    , & Changes in global land monsoon area and total rainfall accumulation over the last half century. Geophys. Res. Lett. 35, L16707 (2008).

  6. 6.

    & Trends in the rainfall pattern over India. Int. J. Climatol. 28, 1453–1469 (2008).

  7. 7.

    , , , & Slowdown of the Walker circulation driven by tropical Indo-Pacific warming. Nature 491, 439–443 (2012).

  8. 8.

    et al. Will the South Asian monsoon overturning circulation stabilize any further? Clim. Dyn. 40, 187–211 (2013).

  9. 9.

    et al. Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing. Nature 441, 73–76 (2006).

  10. 10.

    & Paradox in South Asian summer monsoon circulation change: Lower tropospheric strengthening and upper tropospheric weakening. Geophys. Res. Lett. 41, 2934–2940 (2014).

  11. 11.

    et al. Projected future changes of the Asian Monsoon: A Comparison of CMIP3 and CMIP5 model results. J. Meteorol. Soc. Japn 92, 207–225 (2014).

  12. 12.

    , & Global warming and the weakening of the Asian summer Monsoon circulation: assessments from the CMIP5 models. Clim. Dyn. 45, 1–20 (2014).

  13. 13.

    & Climate change and the South Asian summer monsoon. Nat. Clim. Change 2, 587–595 (2012).

  14. 14.

    et al. Trends and oscillations in the Indian summer monsoon rainfall over the last two millennia. Nat. Commun. 6, 6309 (2015).

  15. 15.

    , , & Climate Phenomena and Their Relevance for Future Regional Climate Change Cambridge University Press (2013).

  16. 16.

    , & Land/sea warming ratio in response to climate change: IPCC AR4 model results and comparison with observations. Geophys. Res. Lett. 34, L02701 (2007).

  17. 17.

    Land–sea heating contrast in an idealized Asian summer monsoon. Clim. Dyn. 21, 11–25 (2003).

  18. 18.

    et al. Thermal controls on the Asian summer monsoon. Scientific Rep. 2, 404 (2012).

  19. 19.

    , , & Summertime land–sea thermal contrast and atmospheric circulation over East Asia in a warming climate—Part I: Past changes and future projections. Clim. Dyn. 43, 2553–2568 (2014).

  20. 20.

    , & Observed temperature trends in the Indian Ocean over 1960–1999 and associated mechanisms. Geophys. Res. Lett. 34, L02606 (2007).

  21. 21.

    et al. Why is Indian Ocean warming consistently? Clim. Change 110, 709–719 (2012).

  22. 22.

    , & Indian Ocean and monsoon coupled interactions in a warming environment. Clim. Dyn. 42, 2439–2454 (2014).

  23. 23.

    Sensitivity of precipitation to sea surface temperature over the tropical summer monsoon region—and its quantification. Clim. Dyn. 43, 1159–1169 (2013).

  24. 24.

    , , & Failure of CMIP5 climate models in simulating post‐1950 decreasing trend of Indian monsoon. Geophys. Res. Lett. 41, 7323–7330 (2014).

  25. 25.

    , , , & Why ensemble mean projection of south Asian monsoon rainfall by CMIP5 models is not reliable? Clim. Dyn. 45, 1–14 (2014).

  26. 26.

    , , , & Future projection of Indian summer monsoon variability under climate change scenario: An assessment from CMIP5 climate models. Global Planet. Change 124, 62–78 (2015).

  27. 27.

    , , & Ocean forcing to changes in global monsoon precipitation over the recent half-century. J. Climate 21, 3833–3852 (2008).

  28. 28.

    , , & The curious case of Indian Ocean warming. J. Climate 27, 8501–8509 (2014).

  29. 29.

    et al. Impacts of Indian Ocean SST biases on the Indian Monsoon: as simulated in a global coupled model. Clim. Dyn. 42, 271–290 (2014).

  30. 30.

    & Poleward shift in Indian summer monsoon low level jetstream under global warming. Clim. Dyn. 45, 337–351 (2014).

  31. 31.

    , & An objective definition of the Indian summer monsoon season and a new perspective on the ENSO–monsoon relationship. Q. J. Roy. Meteorol. Soc. 133, 749–764 (2007).

  32. 32.

    , & Ocean-atmosphere coupling over monsoon regions. Nature 312, 141–143 (1984).

  33. 33.

    In situ evidence of rapid, vertical, irreversible transport of lower tropospheric air into the lower tropical stratosphere by convective cloud turrets and by larger‐scale upwelling in tropical cyclones. J. Geophys. Res. 98, 8665–8681 (1993).

  34. 34.

    et al. The relative roles of upper and lower tropospheric thermal contrasts and tropical influences in driving Asian summer monsoons. J. Geophys. Res. 118, 7024–7045 (2013).

  35. 35.

    , & Sensitivity of tropical tropospheric temperature to sea surface temperature forcing. J. Climate 16, 1283–1301 (2003).

  36. 36.

    & The general circulation model precipitation bias over the southwestern equatorial Indian Ocean and its implications for simulating the South Asian monsoon. Clim. Dyn. 40, 823–838 (2013).

  37. 37.

    Some Simple Solutions for Heat-Induced Tropical Circulation vol. 106, John Wiley & Sons, Ltd (1980).

  38. 38.

    et al. Why the western Pacific subtropical high has extended westward since the late 1970s. J. Climate 22, 2199–2215 (2009).

  39. 39.

    & Evidence of surface cooling from absorbing aerosols. Geophys. Res. Lett. 29, 54-51–54-54 (2002).

  40. 40.

    , & On the response of Indian summer monsoon to aerosol forcing in CMIP5 model simulations. Clim. Dyn. 2, 1–13 (2015).

  41. 41.

    , & Tropospheric cooling and summer monsoon weakening trend over East Asia. Geophys. Res. Lett. 31, L22212 (2004).

  42. 42.

    , , , & Intraseasonal SST-precipitation relationship and its spatial variability over the tropical summer monsoon region. Clim. Dyn. 41, 45–61 (2012).

  43. 43.

    The Asian Monsoon 3-66 (Springer-Verlag, 2006).

  44. 44.

    , & Anthropogenic aerosols and the weakening of the South Asian summer monsoon. Science 334, 502–505 (2011).

  45. 45.

    et al. Atmospheric brown clouds: Impacts on South Asian climate and hydrological cycle. Proc. Natl Acad. Sci. USA 102, 5326–5333 (2005).

  46. 46.

    , & Effects of black carbon aerosols on the Indian monsoon. J.Climate 21, 2869–2882 (2008).

  47. 47.

    , , & Climate effects of black carbon aerosols in China and India. Science 297, 2250–2253 (2002).

  48. 48.

    & Observational relationships between aerosol and Asian monsoon rainfall, and circulation. Geophys. Res. Lett. 33, L21810 (2006).

  49. 49.

    , & Indian Ocean warming during 1958–2004 simulated by a climate system model and its mechanism. Clim. Dyn. 42, 203–217 (2014).

  50. 50.

    , & The role of the aerosol indirect effect in the northern Indian Ocean warming simulated by CMIP5 models. Atmos. Oceanic Sci. Lett. 7, 411–416 (2014).

  51. 51.

    & Role of atmospheric adjustments in the tropical Indian Ocean warming during the 20th century in climate models. Geophys. Res. Lett. 35, L08712 (2008).

  52. 52.

    & Removing ENSO-related variations from the climate record. J. Climate 23, 1957–1978 (2010).

  53. 53.

    , , & Role of air-sea interaction in the long persistence of El Niño-induced North Indian Ocean warming. J. Climate 22, 2023–2038 (2009).

  54. 54.

    & Impact of ENSO on the variability of the Asian-Australian monsoons as simulated in GCM experiments. J. Climate 13, 4287–4309 (2000).

  55. 55.

    & Basin‐wide warming of the Indian Ocean during El Niño and Indian Ocean dipole years. Int. J. Climatol. 27, 1421–1438 (2007).

  56. 56.

    & Net heat flux over the Indian Ocean: trends, driving mechanisms, and uncertainties. Geosci. Remote Sensing Lett. 10, 776–780 (2013).

  57. 57.

    , , & Is a global warming signature emerging in the tropical Pacific? Geophys. Res. Lett. 39, 02701 (2012).

  58. 58.

    , & Are tropical SST trends changing the global teleconnection during La Niña? Geophys. Res. Lett. 37, L12702 (2010).

  59. 59.

    , , & A physical mechanism for North Atlantic SST influence on the Indian summer monsoon. Geophys. Res. Lett. 33, L02706 (2006).

  60. 60.

    , , & Atlantic forced component of the Indian monsoon interannual variability. Geophys. Res. Lett. 35, L04706 (2008).

  61. 61.

    , , , & Oceanic factors controlling the Indian Summer Monsoon onset in a coupled model. Clim. Dyn. 44, 977–1002 (2015).

  62. 62.

    et al. Projected seasonal mean summer monsoon over India and adjoining regions for the twenty-first century. Theor. Appl. Climatol. 1–13, doi:10.1007/s00704-014-1310-0 (2014).

  63. 63.

    & The perfect ocean for drought. Science 299, 691–694 (2003).

  64. 64.

    , , , & Links between Indo-Pacific climate variability and drought in the Monsoon Asia Drought Atlas. Clim. Dyn. 40, 1319–1334 (2013).

  65. 65.

    , & Indian Ocean warming modulates Pacific climate change. Proc. Natl Acad. Sci. USA 109, 18701–18706 (2012).

  66. 66.

    , , & Analysis of the daily rainfall events over India using a new long period (1901–2010) high resolution (0.25 × 0.25) gridded rainfall data set. Clim. Dyn. 1–22, doi:10.1007/s00382-014-2307-1 (2014).

  67. 67.

    Rank Correlation Methods 1 edn ed. Griffin C. Oxford (1948).

  68. 68.

    & Changes in global monsoon precipitation over the past 56 years. Geophys. Res. Lett. 33, L0671 (2006).

  69. 69.

    et al. The NCEP climate forecast system version 2. J. Climate 27, 2185–2208 (2013).

Download references

Acknowledgements

We gratefully acknowledge the financial support given by the Earth System Science Organization, Ministry of Earth Sciences, Government of India, to conduct this research under the National Monsoon Mission (Grant #MM/SERP/CNRS/2013/INT-10/002, Contribution #MM/PASCAL/RP/03).

Author information

Affiliations

  1. Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pashan, Pune 411008, India

    • Mathew Koll Roxy
    • , Kapoor Ritika
    • , Karumuri Ashok
    •  & B. N. Goswami
  2. Department of Environmental Sciences, Fergusson College, University of Pune, Pune 411004, India

    • Kapoor Ritika
  3. Sorbonne Universites (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, LOCEAN Laboratory, 4 place Jussieu, F-75005 Paris, France

    • Pascal Terray
  4. Indo-French Cell for Water Sciences, IISc-IITM-NIO–IRD Joint International Laboratory, IITM, Pune 411008, India

    • Pascal Terray
  5. ESSIC, University of Maryland, College Park, Maryland 20740, USA

    • Raghu Murtugudde
  6. Centre for Earth and Space Sciences, University of Hyderabad, Hyderabad 500046, India

    • Karumuri Ashok
  7. Earth and Climate Science Department, Indian Institute of Science Education and Research, Pune 411008, India

    • B. N. Goswami

Authors

  1. Search for Mathew Koll Roxy in:

  2. Search for Kapoor Ritika in:

  3. Search for Pascal Terray in:

  4. Search for Raghu Murtugudde in:

  5. Search for Karumuri Ashok in:

  6. Search for B. N. Goswami in:

Contributions

M.K.R. designed the study and the model experiment. M.K.R. and K.R. performed the model sensitivity experiments and the analysis. All authors contributed ideas in developing the research, discussed the results and wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Mathew Koll Roxy.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Figures 1-4

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.