The role of the Indian Summer Monsoon variability on Arabian Peninsula summer climate
- 364 Downloads
This study investigates the influence of the Indian Summer Monsoon (ISM) on the atmospheric circulation over the Arabian Peninsula (AP) using the European Centre for Medium Range Weather Forecasts’ twentieth century reanalysis (ERA-20C) for the period 1901–2010. After describing the summer climate of the AP using various dynamic and thermodynamic parameters, we investigate the link between extreme ISMs and atmospheric circulation over the AP on inter-annual time scale. Analysis of composites of different parameters during extreme monsoon (strong and weak) years reveals that the ISM plays an important role in the summer circulation over the AP and adjoining regions. The major noticeable changes in modulating circulation during extreme monsoons are: (1) a strengthening of lower tropospheric northerly winds, westerly winds passing through the Tokar Gap, Shamal winds, and the upper tropospheric easterly jet stream during strong ISM; (2) a northward (southward) shift of the subtropical westerly jet stream during strong (weak) monsoon years; (3) the development of strong upper level ridge above the surface thermal low during strong ISM years, which result in a baroclinic structure over the AP and adjoining regions; (4) an increase in adiabatic warming, and hence aridity, over the AP during strong monsoon years, caused by intense subsidence of the middle to upper troposphere due to zonal overturning circulation; and (5) convective instability during strong monsoon years caused by an intensification of the upward motion over the southern AP. Furthermore, during strong monsoons, the availability of excess moisture leads to atmospheric instability, which in turn triggers the formation of clouds that lead to more rainfall over the southwestern AP. Finally, the westward propagation of a Gill-type Rossby waves induced by the ISM play an important role in the variations of the AP summer climate by enhancing the warm core structure over the AP and through their interaction with the midlatitude westerlies during strong monsoons.
KeywordsArabian Peninsula Indian Summer Monsoon Warm core structure Rossby wave
This study was supported by the King Abdullah University of Science and Technology (KAUST), Saudi Arabia and the Saudi ARAMCO-KAUST Marine Environmental Research Center (SAKMERC). It made use of the Supercomputing Laboratory and computer clusters at KAUST. The authors thank the anonymous reviewers for the insightful comments on the manuscript.
- Attada R, Dasari HP, Chowdary JS, Yadav RK, Omar K, Ibrahim H (2018) Surface air temperature variability over the Arabian Peninsula and its links to circulation patterns. Int J Climatol (Accepted) Google Scholar
- Babu CA, Samah AA, Varikoden H (2011) Rainfall climatology over Middle East Region and its variability. Int J Water Resour Arid Environ 1:180–192Google Scholar
- Holton J, Hakim GJ (2012) An introduction to dynamic meteorology, vol 88, 5th edn, ISBN: 9780123848673Google Scholar
- Jennings RP, Singarayer J, Stone EJ et al (2015) The greening of Arabia: multiple opportunities for human occupation of the Arabian Peninsula during the Late Pleistocene inferred from an ensemble of climate model simulations. Quatern Int 382:181–199. https://doi.org/10.1016/j.quaint.2015.01.006 CrossRefGoogle Scholar
- Köppen W (1936) Das geographische System der Klimate. In: Koppen W, Geiger R (eds) Handbuch der Klimatologie, vol 1. GebrBorntrager, Berlin, pp 1–44Google Scholar
- Rajeevan M, Bhate J, Kale JD, Lal B (2006) A high-resolution daily gridded rainfall for the Indian region: analysis of break and active monsoon spells. Curr Sci 91:296–306Google Scholar
- Tyrlis E, Skerlak B, Sprenger M, Wernli H, Zittis G, Lelieveld J (2014) On the linkage between the Asian summer monsoon and tropopause fold activity over the Eastern Mediterranean and the Middle East. J Geophys Res 119:3202–3221Google Scholar
- Wilks D (2006) Statistical methods in the atmospheric sciences: an introduction, 2nd edn. Academic Press, CambridgeGoogle Scholar