Past and Future Trends in Frequency of Heavy Rainfall Events over Pakistan

Farah Ikram, M. Afzaal, Syed Ahsan Ali Bukhari, Burhan Ahmed


The South Asian summer monsoon directly affects the lives of almost one-half of the world’s population, with substantial variability in the monsoon season such as fluctuating between wet (heavy precipitation) and dry spells. This study presents the changes in temperature and precipitation over Pakistan under two different RCP scenarios of a statistically downscaled CMIP5 Coupled General Circulation Model. The analyses are extended to seasonal scale with a focus on the Summer Monsoon season and heavy precipitation events. There is a positive change in mean temperature of 2.7°C under RCP 4.5 scenario and 8.3 °C under RCP 8.5 scenario till the end of this century. The seasonal cycle shows that the winters are warming more than summers with an increase in temperature of 6 to 8°C in the 21st century with respect to baseline (1975-2005). The spatial analysis of both RCPs shows a much sharper increase in mean temperature of the northern areas with respect to the southern areas of Pakistan. Whereas, the precipitation maxima in the century show an overall increase of 3 to 4 mm/day at annual time scale. Both scenarios show a shift in the monsoon region towards the northeast along with a dipole like a pattern over the region (increase in JJAS mean precipitation over monsoon belt with a coexisting decreasing trend of up to 2 mm/day over Punjab, some areas of Sindh and Balochistan). Summer mean temperature shows more warming after mid-century in lower areas of Pakistan including Punjab, southern parts of KPK and upper areas of Balochistan. Two indices have been defined for the summer season. First is the frequency of extreme precipitation events based on the thresholds of daily precipitation as 50 mm/day, 100 mm/day and the second are for dry days as < 1 mm/day. Results show a significant increase in a number of dry days over the selected area of Pakistan, 130/year under RCP4.5 scenario and 420/year over under RCP 8.5 Scenario. Spatial analysis of dry days show an increasing trend and their decadal variability in future projections under both RCP scenarios show that frequent dry days extend towards the north. Heavy rainfall events analysis show intense rainfall events over Pakistan being confined to only the key monsoon region and coastal area of Sindh having return periods of 1 to 2 years. The temporal variability of heavy rainfall frequency indicate decreasing trend with an increase in the intensity of rainfall under both RCP scenarios.

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Ahmad, B., W. Iqbal., S. A. A. Bukhari., G. Rasul, A. B. Shreshtha, and J. M. Shea, 2015: Generation of High-Resolution Gridded Climate Fields for the Upper Indus River Basin by Downscaling Cmip5 Outputs. Journal of Earth Science & Climatic Change, 6(2), p.1.

Ahmed, K. F., G. Wang, J. Silander, A. M.Wilson, J. M. Allen, R. Horton, and R. Anyah, 2013: Statistical downscaling and bias correction of climate model outputs for climate change impact assessment in the US northeast. Global and Planetary Change, 100, pp.320-332.

Ashfaq, M., Y. Shi, W. W. Tung, R. J. Trapp, X. Gao, J. S. Pal, and N. S. Diffenbaugh, 2009: Suppression of south Asian summer monsoon precipitation in the 21st century. Geophysical Research Letters, 36(1).

Beniston, M., H. F. Diaz, and R. S. Bradley, 1997: Climatic change at high elevation sites: an overview. Climatic Change, 36(3-4), pp.233-251.

Dash, S. K., M. A. Kulkarni, U. C. Mohanty, and K. Prasad, 2009: Changes in the characteristics of rain events in India. Journal of Geophysical Research: Atmospheres, 114(D10).

Gadgil, S., and K. R. Kumar, 2006: The Asian monsoon agriculture and economy. The Asian Monsoon, pp.651-683.

Goswami, B. N., V. Venugopal, D. Sengupta, M. S. Madhusoodanan, and P. K. Xavier, 2006: Increasing trend of extreme rain events over India in a warming environment. Science, 314(5804), pp.1442-1445.

Guo, L., A. G. Turner, and E. J. Highwood, 2015: Impacts of 20th century aerosol emissions on the South Asian monsoon in the CMIP5 models. Atmospheric Chemistry and Physics, 15(11), pp.6367-6378

Hsu, P. C., 2016: Global Monsoon in a Changing Climate. In The Monsoons and Climate Change (pp. 7-24). Springer International Publishing.

Hsu, P. C., T. Li, H. Murakami, and A. Kitoh, 2013: Future change of the global monsoon revealed from 19 CMIP5 models. Journal of Geophysical Research: Atmospheres, 118(3), pp.1247-1260

Hussain, M. S., and S. Lee, 2013: The regional and the seasonal variability of extreme precipitation trends in Pakistan. Asia-Pacific Journal of Atmospheric Sciences, 49(4), pp.421-441

Iqbal, W., and M. Zahid, 2014: Historical and Future Trends of Summer Mean Air Temperature over South Asia. Pakistan Journal of Meteorology Vol, 10(20).

Kitoh, A., H. Endo, K. K. Kumar, I. F. Cavalcanti, P. Goswami, and T. Zhou, 2013: Monsoons in a changing world: a regional perspective in a global context. Journal of Geophysical Research: Atmospheres, 118(8), pp.3053-3065.

Krishnamurthy, V., and J. L. Kinter III, 2003: The Indian monsoon and its relation to global climate variability. In Global Climate (pp. 186-236). Springer Berlin Heidelberg.

Kulkarni, A., 2012: Weakening of Indian summer monsoon rainfall in warming environment. Theoretical and Applied Climatology, 109(3-4), pp.447-459.

Latif, M., F. S. Syed, and A. Hannachi, 2016: Rainfall trends in the South Asian summer monsoon and its related large-scale dynamics with focus over Pakistan. Climate Dynamics, pp.1-17.

Liu, X., and B. Chen, 2000: Climatic warming in the Tibetan Plateau during recent decades. International journal of climatology, 20(14), pp.1729-1742.

Liu, X., Z. Y. Yin, X. Shao, and N. Qin, 2006: Temporal trends and variability of daily maximum and minimum, extreme temperature events, and growing season length over the eastern and central Tibetan Plateau during 1961–2003. Journal of Geophysical Research: Atmospheres, 111(D19).

Loo, Y. Y., L. Billa, and A. Singh, 2015: Effect of climate change on seasonal monsoon in Asia and its impact on the variability of monsoon rainfall in Southeast Asia. Geoscience Frontiers, 6(6), pp.817-823.

McGregor, G. R., C. A. Ferro, and D. B. Stephenson, 2005: Projected changes in extreme weather and climate events in Europe. In Extreme Weather Events and Public Health Responses (pp. 13-23). Springer Berlin Heidelberg.

Meehl, G. A., J. M. Arblaster, and W. D. Collins, 2008: Effects of black carbon aerosols on the Indian monsoon. Journal of Climate, 21(12), pp.2869-2882.

Meehl, G. A., L. Goddard, J. Murphy, R. J. Stouffer, G. Boer, G. Danabasoglu, K. Dixon, M .A. Giorgetta, A. M. Greene, E. Hawkins, and G. Hegerl, 2009: Decadal prediction: can it be skillful? Bulletin of the American Meteorological Society, 90(10), p.1467.

Meehl, G.A., T. F. Stocker, W. D. Collins, P. Friedlingstein, , A. T. Gaye, J. M. Gregory, A. Kitoh, R. Knutti, J. M. Murphy, A. Noda, and, S. C. Raper, 2007: Global climate projections. Climate change, 3495, pp.747-845.

Neale, R. B., C. C. Chen, A. Gettelman, P. H. Lauritzen, S. Park, D. L. Williamson, A. J. Conley, R. Garcia, D. Kinnison, J. F. Lamarque, and D. Marsh, 2010: Description of the NCAR community atmosphere model (CAM 5.0). NCAR Tech. Note NCAR/TN-486+ STR.

Pepin, N. C., and D. J. Seidel, 2005: A global comparison of surface and free‐air temperatures at high elevations. Journal of Geophysical Research: Atmospheres, 110(D3).

Pepin, N. C., and J. D. Lundquist, 2008: Temperature trends at high elevations: patterns across the globe. Geophysical Research Letters, 35(14).

Rajbhandari, R., A. B. Shrestha, A. Kulkarni, S. K. Patwardhan, and S. R Bajracharya, 2015: Projected changes in climate over the Indus river basin using a high resolution regional climate model (PRECIS). Climate Dynamics, 44(1-2), pp.339-357.

Rangwala, I., and J. R. Miller, 2012: Climate change in mountains: a review of elevation-dependent warming and its possible causes. Climatic Change, 114(3-4), pp.527-547.

Rangwala, I., J. R. Miller, G. L. Russell, and M. Xu, 2010: Using a global climate model to evaluate the influences of water vapor, snow cover and atmospheric aerosol on warming in the Tibetan Plateau during the twenty-first century. Climate Dynamics, 34(6), pp.859-872.

Rasul, G., Q. Dahe, and Q. Z. Chaudhry, 2008: Global warming and melting glaciers along southern slopes of HKH range. Pak. Jr. of Meteorology, 5(9).

Rasul, G., Q. Z. Chaudhry, A. Mahmood, K. W. Hyder, and Q. Dahe, 2011: Glaciers and glacial lakes under changing climate in Pakistan. Pakistan Journal of Meteorology, 8(15), pp.1-8.

Roxy, M. K., K. Ritika, P. Terray, R. Murtugudde, K. Ashok, and B. N. Goswami, 2015: Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient. Nature communications, 6.

Schwierz, C., C. Appenzeller, H. C. Davies, M. A. Liniger, W. Müller, T. F. Stocker and M. Yoshimori, 2006: Challenges posed by and approaches to the study of seasonal-to-decadal climate variability. Climatic Change, 79(1-2), pp.31-63.

Semenov, V., and L. Bengtsson, 2002: Secular trends in daily precipitation characteristics: greenhouse gas simulation with a coupled AOGCM. Climate Dynamics, 19(2), pp.123-140.

Shenbin, C., L. Yunfeng, and A. Thomas, 2006: Climatic change on the Tibetan Plateau: potential evapotranspiration trends from 1961–2000. Climatic Change, 76(3-4), pp.291-319.

Sivakumar, M.V., and R. Stefanski, 2010: Climate Change in South Asia. In Climate change and food security in South Asia (pp. 13-30). Springer Netherlands.

Solomon, S. ed., 2007: Climate change 2007-the physical science basis: Working group I contribution to the fourth assessment report of the IPCC (Vol. 4). Cambridge University Press.

Syed, F.S., and F. Kucharski, 2015: Statistically related coupled modes of South Asian summer monsoon interannual variability in the tropics. Atmospheric Science Letters.

Tebaldi, C., K. Hayhoe, J. M. Arblaster, and G. A. Meehl, 2006: Going to the extremes. Climatic change, 79(3-4), pp.185-211.

Trenberth, K. E., and J. T. Fasullo, 2013: An apparent hiatus in global warming? Earth's Future, 1(1), pp.19-32.

Turner, A. G., and J. M. Slingo, 2009: Subseasonal extremes of precipitation and active‐break cycles of the Indian summer monsoon in a climate‐change scenario. Quarterly Journal of the Royal Meteorological Society, 135(640), pp.549-567.

Turner, A.G., and H. Annamalai, 2012: Climate change and the South Asian summer monsoon. Nature Climate Change, 2(8), pp.587-595.

W. W. Immerzeel, L. P. H. Van Beek, M. Konz, A. B. Shrestha, and M. F. P. Bierkens, 2012: Hydrological response to climate change in a glacierized catchment in the Himalayas. Climatic change, 110(3-4), pp.721-736.

Wang, B., J. Liu, H. J. Kim, P. J. Webster, and S. Y. Yim, 2012: Recent change of the global monsoon precipitation (1979–2008). Climate Dynamics, 39(5), pp.1123-1135.

Wood, A. W., L. R. Leung, V. Sridhar, and D. P. Lettenmaier, 2004: Hydrologic implications of dynamical and statistical approaches to downscaling climate model outputs. Climatic change, 62(1-3), pp.189-216.

Yatagai, A., K. Kamiguchi, O. Arakawa, A. Hamada, N. Yasutomi, and A. Kitoh, 2012: APHRODITE: Constructing a long-term daily gridded precipitation dataset for Asia based on a dense network of rain gauges. Bulletin of the American Meteorological Society, 93(9), pp.1401-1415.

You, Q., S. Kang, N. Pepin, W. A. Flügel, Y. Yan, H. Behrawan, and J. Huang, 2010: Relationship between temperature trend magnitude, elevation and mean temperature in the Tibetan Plateau from homogenized surface stations and reanalysis data. Global and Planetary Change, 71(1), pp.124-133.

Zahid, M., and G. Rasul, 2011: Thermal classification of Pakistan. Atmospheric and Climate Sciences, 1(04), p.206.


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