Abstract
The impact of land-sea thermal contrast on the South Asian summer monsoon (SASM) was investigated by calculating the atmospheric heat sources (AHS) and baroclinic component with ERA5 data for the period 1979–2019. Using diagnostic and statistical methods, it was found that the thermal contrast between the Tibetan Plateau (TP) and the tropical Indian Ocean (TIO) affects the South Asian monsoon circulation through the meridional temperature gradient in the upper troposphere. The seasonal changes of the AHS of the TP and TIO are reversed. In summer, the TP is the strongest at the same latitude whereas the TIO is the weakest, and the thermal contrast is the most obvious. The heat sources of the TP and TIO are located on the north and south side of the strong baroclinic area of the SASM region, respectively, and both of which are dominated by deep convective heating in the upper troposphere. The TP-TIO regional meridional thermal contrast index (QI) based on the AHS, and the SASM index (MI) based on baroclinicity were found to be strongly positively correlated. In years of abnormally high QI, the thermal contrast between the TP and TIO is strong in summer, which warms the upper troposphere over Eurasia and cools it over the TIO. The stronger temperature gradient enhances the baroclinicity in the troposphere, which results in a strengthening of the low-level westerly airflow and the upper-level easterly airflow. The anomalous winds strengthen the South Asian high (SAH), with the warmer center in the upper troposphere, and the enhanced Walker circulation over the equatorial Indian Ocean. Finally, the anomalous circulation leads to much more precipitation over the SASM region. The influence of abnormally low QI is almost the opposite.
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References
Chou C (2003). Land-sea heating contrast in an idealized Asian summer monsoon. Clim Dyn, 21(1): 11–25
Dai A G, Li H M, Sun Y, Hong L C, Ho L, Chou C, Zhou T J (2013). The relative roles of upper and lower tropospheric thermal contrasts and tropical influences in driving Asian summer monsoons. J Geophys Res, 118(13): 7024–7045
Duan A M, Wu G X (2005). Role of the Tibetan Plateau thermal forcing in the summer climate patterns over subtropical Asia. Clim Dyn, 24 (7–8): 793–807
Fu C, Fletcher J O (1985). The relationship between Tibet-tropical ocean thermal contrast and interannual variability of Indian monsoon rainfall. J Appl Meteorol, 24(8): 841–847
Goswami B N, Krishnamurthy V, Annmalai H (1999). A broad-scale circulation index for the interannual variability of the Indian summer monsoon. Q J R Meteorol Soc, 125(554): 611–633
Guan Z Y, Xu J J, Guo P W, Wang C (1997). The structure and variations of Asian summer monsoon reveled by barotropic and baroclinic modes the baroclinic mode analysis. Acta Meteorol Sin, 55(02): 19–26 (in Chinese)
Guan Z (2000). The variations of Asian monsoon as revealed by the variations of kinetic energy of barotropic/baroclinic modes of the wind field. Transactions of Atmospheric Sciences, 23(03): 313–322 (in Chinese)
Hansen J, Ruedy R, Sato M, Lo K (2010). Global surface temperature change. Rev Geophys, 48(4): RG4004
He H Y, Sui C H, Jian M Q, Wen Z P, Lan G (2003). The evolution of tropospheric temperature field and its relationship with the onset of Asian summer monsoon. J Meteorol Soc Jpn, 81(5): 1201–1223
He Y L, Huang J P, Ji M J (2014). Impact of land-sea thermal contrast on interdecadal variation in circulation and blocking. Clim Dyn, 43(12): 3267–3279
Hersbach H, Bell B, Berrisford P, Hirahara S, Horányi A, Muñoz-Sabater J, Nicolas J, Peubey C, Radu R, Schepers D, Simmons A, Soci C, Abdalla S, Abellan X, Balsamo G, Bechtold P, Biavati G, Bidlot J, Bonavita M, De Chiara G, Dahlgren P, Dee D, Diamantakis M, Dragani R, Flemming J, Forbes R, Fuentes M, Geer A, Haimberger L, Healy S, Hogan R J, Hólm E, Janisková M, Keeley S, Laloyaux P, Lopez P, Lupu C, Radnoti G, de Rosnay P, Rozum I, Vamborg F, Villaume S, Thépaut J (2020). The ERA5 global reanalysis. Q J R Meteorol Soc, 146(730): 1999–2049.
Huang J Y, Li Q X (2015). Methods for Statistical Analysis of Meteorological Data. Beijing: Meteorology Press (in Chinese)
Holton J R, Hakim G J (2004). An Introduction to Dynamic Meteorology. Burlington: Elsevier Acad
Kripalani R H, Kulkarni A, Sabade S S, Khandekar M L (2003). Indian Monsoon variability in a global warming scenario. Nat Hazards, 29 (2): 189–206
Li C F, Yanai M (1996). The onset and interannual variability of the Asian summer monsoon in relation to land-sea thermal contrast. J Clim, 9(2): 358–375
Li J P, Zeng Q C (2002). A unified monsoon index. Geophys Res Lett, 29(8): 115–1–115–4.
Liebmann B, Smith C A (1996). Description of a complete (interpolated)— outgoing longwave radiation dataset. Bull Amer Meteor Soc, 77(6): 1275–1277
Liu X, Wu G X, Liu Y M, Liu P (2002). Diabatic heating over the Tibetan Plateau and seasonal variastions of the Asian Circulation and summer monsoon. Chin J Atmos Sci, 6: 781–793 (in Chinese)
Liu X, Yanai M (2001). Relationship between the Indian monsoon rainfall and the tropospheric temperature over the Eurasia Continent. Q J R Meteorol Soc, 127(573): 909–937
Liu Y M, Wu G X, Hong J L, Dong B W, Duan A M, Bao Q, Zhou T J (2012). Revisiting Asian monsoon formation and change associated with Tibetan Plateau forcing: I. Formation. Clim Dyn, 39(5): 1169–1181
Liu Y M, Wu G X, Liu H, Liu P (1999). The effect of spatially nonuniform heating on the formation and variation of subtropical high part III: condensation heating and south Asia high and western Pacific. Acta Meteorol Sin, 57(5): 525–538 (in Chinese)
Luo X Q, Xu J J (2019). Estimate of atmospheric heat source over Tibetan Plateau and its uncertainties. Climate Change Research, 15 (1): 33–40 (in Chinese)
Luo X Q, Xu J J, Li K (2019). A review of atmospheric heat sources over the Tibetan Plateau. J Guangdong Ocean Univ, 39(06): 130–136 (in Chinese)
Naveendrakumar G, Vithanage M, Kwon H H, Chandrasekara S S K, Iqbal M C, Pathmarajah S, Fernando W C D K, Obeysekera J (2019). South Asian perspective on temperature and rainfall extremes: a review. Atmos Res, 225: 110–120
Parthasarathy B, Kumar K R, Kothawale D R (1992). Indian summer monsoon rainfall indices: 1871–1990. Meteorological Magazine, 121 (1441): 174–186
Roxy M K, Ritika K, Terray P, Murtugudde R, Ashok K, Goswami B N (2015). Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient. Nat Commun, 6 (1): 7423
Sontakke N A, Pant G B, Singh N (1993). Construction of all-India summer monsoon rainfall series for the period 1844–1991. J Clim, 6 (9): 1807–1811
Sun X R, Chen L X, He J H (2002). Index of the sea thermal difference and its relation to interannual variation of summer circulation and rainfall over East Asian. Acta Meteorol Sin, 60(02): 164–172 (in Chinese)
Sun Y, Ding Y H, Dai A G (2010). Changing links between South Asian summer monsoon circulation and tropospheric land-sea thermal contrasts under a warming scenario, Geophys Res Lett, 37(2):195–205
Turner A G, Annamalai H (2012). Climate change and the South Asian summer monsoon. Nat Clim Chang, 2(8): 587–595
Tu H W, Tian H Y, Xu X, Zhang R (2020). Influence of the south-north displacement of South Asia High on the distribution of atmospheric composition in the upper troposphere-lower stratosphere over the Asian Monsoon Region. Plateau Meteorol, 39(2): 333–346
Wang B, Fan Z (1999). Choice of South Asian summer monsoon indices. Bull Am Meteorol Soc, 80(4): 629–638
Wang B, Liu J, Kim H J, Webster P J, Yim S Y, Xiang B (2013). Northern Hemisphere summer monsoon intensified by mega-El Nino/southern oscillation and Atlantic multidecadal oscillation. Proc Natl Acad Sci USA, 110(14): 5347–5352
Wang P X, Wang B, Cheng H, Fasullo J, Guo Z T, Kiefer T, Liu Z Y (2017). The global monsoon across time scales: mechanisms and outstanding issues. Earth Sci Rev, 174: 84–121
Wang Y N, Zhang B, Chen L X, He J H, Li W, Chen H (2008). Relationship between the atmospheric heat source over Tibetan Plateau and the heat source and general circulation over East Asia. Sci Bull (Beijing), 53(21): 3387–3394
Webster P J, Magaña V O, Palmer T N, Shukla J, Tomas R A, Yanai M, Yasunari T (1998). Monsoons: processes, predictability, and the prospects for prediction. J Geophys Res D Atmospheres, 103(C7): 14451–14510
Webster P J, Yang S (1992). Monsoon and Enso: selectively interactive systems. Q J R Meteorol Soc, 118(507): 877–926
Wei W (2015). The interannual shift of the South Asia High and its relation with the Asian summer monsoon. Dissertation for the Doctoral Degree. Beijing: Chinese Academy of Meteorological Sciences (in Chinese)
Wu G X, Duan A M, Liu Y M, Yang J H, Liu B Q, Ren S L, Zhang Y N, Wang T M, Liang X Y, Guan Y (2013). Recent advances in the study on the dynamics of the Asian summer monsoon onset. Chin J Atmos Sci, 37(2): 211–228 (in Chinese)
Wu G X, Bian H, Liu Y M, Bao Q, Ren R C, Liu B Q (2016). Recent progresses on dynamics of the Tibetan Plateau and Asian summer monsoon. Chin J Atmos Sci, 40(1): 22–32 (in Chinese)
Wu G, Liu Y (2003). Summertime quadruplet heating pattern in the subtropics and the associated atmospheric circulation. Geophys Res Lett, 30(5): 5–1
Wu G, Liu Y, He B, Bao Q, Duan A, Jin F F (2012). Thermal controls on the Asian summer monsoon. Sci Rep, 2(1): 404
Wu G X, Liu Y M, Liu X, Duan A M, Liang X Y (2005). How the heating over the Tibetan Plateau affects the Asian climate in summer. Chinese Journal of Atmospheric Sciences, 29(1):47–56 + 167–168 (in Chinese)
Xu J J, Chan J C L (2002). Relationship between the planetary—scale circulation over East Asia and the intensity of the South Asian Summer Monsoon. Geophys Res Lett, 29(18): 1866
Yanai M, Li C F, Song Z S (1992). Seasonal heating of the Tibetan Plateau and its effects on the evolution of the Asian summer monsoon. J Meteorol Soc Jpn, 70(1B): 319–351
Yanai M, Tomita T (1998). Seasonal and interannual variability of atmospheric heat sources and moisture sinks as determined from NCEP-NCAR reanalysis. J Clim, 11(3): 463–482
Yanai M, Wu G X (2006). Effects of the Tibetan plateau. In: The Asian Monsoon. Heidelberg: Springer, 513–549
You Q, Min J, Zhang W, Pepin N, Kang S (2015). Comparison of multiple datasets with gridded precipitation observations over the Tibetan Plateau. Clim Dyn, 45(3–4): 791–806
Zhang Y, Fan G, Hua W, Zhang Y, Wang B, Lai X (2017). Differences in atmospheric heat source between the Tibetan Plateau-South Asia region and the southern Indian Ocean and their impacts on the Indian summer monsoon outbreak. J Meteorol Res, 31(3): 540–554
Zhan R F, Li J P (2008). The effect of atmospheric heat source in the Tibetan Plateau and the tropical Northwest Pacific Ocean on the interdecadal variation of summer stratospheric-tropospheric water vapor exchange in Asia. Sci China Ser D Earth Sci, 38(8): 1028–1040 (in Chinese)
Zhao Y, Duan A M, Wu G X, Sun R Z (2019). Response of the Indian ocean to the Tibetan Plateau thermal forcing in late spring. J Clim, 32 (20): 6917–6938
Acknowledgements
This research is supported by the the Second Tibetan Plateau Scientific Expedition and Research (STEP) Program (No. 2019QZKK0105), the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA20060501) and the 2019 Non-funded Science and Technology Research Project of Zhanjiang (No. 200518174546338).
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Luo, X., Xu, J., Zhang, Y. et al. Relationship between the Tibetan Plateau-tropical Indian Ocean thermal contrast and the South Asian summer monsoon. Front. Earth Sci. 15, 151–166 (2021). https://doi.org/10.1007/s11707-020-0846-9
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DOI: https://doi.org/10.1007/s11707-020-0846-9