On the relationship between zonal wind variations and precipitation of southern regions of Iran

Document Type : Research Paper

Authors

• Amin Shirvani ¹
• Noushin Ahmadi Baseri ²

¹ Shiraz University

² فارغ التحصیل کارشناسی ارشد هواشناسی کشاورزی، بخش مهندسی آب، دانشکده کشاورزی، دانشگاه شیراز، ایران.

Abstract

In this study, the relationship between the precipitation over the southern areas of Iran and zonal wind over the Middle East was investigated. The monthly zonal wind data at 200hPa over the Middle East was selected from reanalysis NCEP-NCAR. The principal components analysis was applied to extract the signal modes of the winter (JFM) wind variations. The first empirical orthogonal function was spatially plotted and those grid points with high loading, which had the important role in the first principal component, were determined. These grid points are located in 15 to 22.5 and 27.5 to 42.5. The average of zonal wind within this area was considered as a regional index and the relationship between this index and winter precipitation for 11 synoptic stations in the south of Iran for 1968-2010 was investigated. The results indicated that there is a positive significant correlation at 5% level between wind index and precipitation over the most stations. The constructed wind index has stronger relationship with precipitation over the study area in comparison with southern oscillation index and Persian Gulf sea surface temperature.

Keywords

• Principal components analysis
• Empirical orthogonal functions
• Zonal wind
• precipitation
• Iran

20.1001.1.20086377.1397.11.39.4.1

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References

منابع:

1)       Ahrens, C. D .2003. Meteorology today. Thomson Brooks/Cole, CA, USA, 7: 292-299.

2)       Barlow, M., Wheeler, M., Lyon, B. and Cullen, H. 2005. Modulation of daily precipitation over southwest Asia by the Madden–Julian oscillation. Monthly Weather Review. 133: 3579- 3594.

3)       Dezfuli, A.K., Karamouz, M. and Araghinejad, S. 2010. On the relationship of regional meteorological drought with SOI and NAO over southwest Iran. Theoretical and Applied Climatology. 100(1-2): 57-66.

4)       Esteban, M.A. and Chen, Y.L. 2008. The impact of trade wind strength on precipitation over the windward side of the island of Hawaii. Monthly Weather Review. 136(3): 913-928.

5)       Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Leetmaa, A., Reynolds, R., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowiak, J., Mo, K. C., Ropelewski, C., Wang, J., Jenne, R. and Joseph.  D. 1996. The NCEP/NCAR 40-Year reanalysis project. Bulletin of the American Meteorological Society. 77: 437- 471.

6)       Kang, I. S. 1990. Influence of zonal mean flow change on stationary wave fluctuations. Journal of Atmospheric Science. 47: 141-147.

7)       Krishnamurti, T. N. 1961. The subtropical jet stream of winter. Journal of Meteorology. 18: 172-191.

8)       Lau, K. M., Kim, K-M. and Yang, S. 2000. Dynamical and boundary forcing characteristics of regional components of the Asian summer monsoon. Journal of Climate.13: 2461- 2482.

9)       Masoodian, S. A. and Mohammadi, B. 2011. Analysis of jet stream frequencies associated with super Heavy rainfalls of Iran. Iran-Water Resources Research. 7: 80-91 (In Persian).

10)   Murakami, T. and Unninayar, M. 1977. Atmospheric circulation during December 1970 through February 1971. Monthly Weather Review. 105: 1024- 1038.

11)   Naidu, C.V., Krishna, K.M., Rao, S.R., Kumar, O.B., Durgalakshmi, K. and Ramakrishna, S.S.V.S. 2011. Variations of Indian summer monsoon rainfall induce the weakening of easterly jet stream in the warming environment?. Global and Planetary Change.75: 21-30.

12)   Nazemosadat, M.  J. 1998.  The Persian Gulf sea surface temperature as a drought diagnostic for southern parts of Iran. Drought News Network. 10: 12-14.

13)   Nazemosadat, M. J., Ansaribasir, A. and Pishvaei, M. 2007. Significance level in the ENSO- based prediction of autumnal dryness and wetness in Iran. Iran Water Resources Research. 3(1): 12-24 (In Persian).

14)   Nazemosadat, M.J. and Ghaedamini, H. 2010. On the relationships between the Madden–Julian oscillation and precipitation variability in southern Iran and the Arabian Peninsula: Atmospheric circulation analysis. Journal of Climate. 23: 887-904.

15)   Nazemosadat, M. J. and Shirvani, A. 2006. Prediction of winter precipitation in southern regions of Iran using surface temperature of Persian Gulf: Modeling of conventional correlation analysis. The Scientific Journal of Agriculture. 29 (2): 65-77 (In Persian).

16)   Raziei, T., Mofidi, A., Santos, J.A. and Bordi, I. 2012. Spatial patterns and regimes of daily precipitation in Iran in relation to large‐scale atmospheric circulation. International Journal of Climatology. 32(8): 1226-1237.

17)   Smith, T.M., Reynolds, R.W., Peterson, T.C. and Lawrimore, J. 2008. Improvements to NOAA’s historical merged land–ocean surface temperature analysis (1880–2006). Journal of Climate.  21: 2283- 2296.

18)   Watterson, I. G. 2001.  Wind-induced rainfall and surface temperature anomalies in the Australian region. Journal of Climate. 14: 1901–1922.

19)   Yang, S., Lau, K.M. and Kim, K.M. 2002. Variations of the East Asian jet stream and Asian–Pacific–American winter climate anomalies. Journal of Climate. 15: 306- 325.