Characteristics of Central Southwest Asian Water Budgets and Their Impacts on Regional Climate

Khalid M. Malik, Peter A. Taylor, Kit Szeto, Azmat Hayat Khan

Climate Research Division, Environment Canada, Gatineau, Canada.
National Agromet Center, Pakistan Meteorological Department, Islamabad, Pakistan.
National Drought Monitoring Center, Pakistan Meteorological Department, Islamabad, Pakistan.
York University, Toronto, Canada.

DOI: 10.4236/acs.2013.32027                

Abstract

Water budgets terms, evapotranspiration (E), precipitation (P), runoff (N), moisture convergence (MC) and both surface as well as atmospheric residual terms have been computed with National Centers for Environmental Prediction (NCEP) (1948-2007) and European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 (1958-2001) reanalysis data sets for Central Southwest Asia (CSWA).The domain of the study is 45° - 75°E & 25° - 40°N. Only the land area has been used in these calculations. It is noted in the comparison of both reanalysis data sets with Global Precipitation Climatology Centre (GPCC) that all three data sets record different precipitation before 1970. The maximum is from NCEP and the minimum with ERA-40. However, after 1970 all the data sets record almost the same precipitation. ERA-40 computes two phases of MC. Before 1975, the domain acts as a moisture source, whereas after 1975 it behaves as a moisture sink. The region CSWA is divided into six sub areas with rotational principle factor analysis and we distinguish them by different approached weather systems acting on each area. Finally, NCEP yearly precipitation is further divided into seasons; winter (November to April) and summer (May to October) and two phases have been noted. The variation in winter precipitation is more than summer during last 60-year analysis.

Keywords

Water Budgets; Drought over Central Southwest Asia; Moisture Flux Convergence; Principle Component Analysis; Climate Change

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	K?ppen-Geiger, “Climate zones,” Centre for International Development at Hervard University, 1999.
[2]	D. Martyn, “Climates of the World,” Elsevier, Amsterdam, 1992, 436 p.
[3]	J. Roads, et al., “CSE Water and Energy Budgets in the NCEP-DOE Reanalysis II,” Journal of Hydrometeorology, Vol. 3, No. 3, 2002, pp. 227-248. doi:10.1175/1525-7541(2002)003<0227: CWAEBI>2.0.CO;2
[4]	T. Dinku, et al., “Comparison of Global Gridded Precipitation Products over a Mountainous Region of Africa,” International Journal of Climatology, Vol. 28, No. 12, 2008, pp. 1627-1638. doi:10.1002/ joc.1669
[5]	ECMWF, ECMWF Reanalysis Data. http://data.ecmwf.int/data/d/era40_daily/
[6]	S. M. Uppala, et al., “The ERA-40 Re-Analysis,” Quarterly Journal of the Royal Meteorological Society, Vol. 131, No. 612, 2005, pp. 2961-3012. doi:10.1256/qj.04.176
[7]	R. Kistler, et al., “The NCEP-NCAR 50-Year Reanalysis: Monthly Means CD-ROM and Documentation,” Bulletin of the American Meteorological Society, Vol. 82, No. 2, 2001, pp. 247-267. doi:10.1175/1520-0477(2001)082<0247:TNNYRM>2.3.CO;2
[8]	L. L. Thurstone, “Multiple Factor Analysis,” Psychological Review, Vol. 38, No. 5, 1931, pp. 406-427. doi:10.1037/h0069792
[9]	K. K. Szeto, et al., “The MAGS Water and Energy Budget Study,” Journal of Hydrometeorology, Vol. 9, No. 1, 2008, pp. 96-115. doi:10.1175/2007JHM810.1
[10]	NCEP, NECP Reanalysis Data. http://www.cdc.noaa.gov/cdc/reanalysis/reanalysis.shtml
[11]	J. L. Liu, et al., “Characteristics of the Water Vapour Transport over the Mackenzie River Basin during the 1994/95 Water Year,” Atmosphere-Ocean, Vol. 40, No. 2, 2002, pp. 101-111. doi:10.3137/ao.400202
[12]	N. Panigrahy, et al., “Algorithms for Computerized Estimation of Thiessen Weights,” Journal of Computing in Civil Engineering, Vol. 23, No. 4, 2009, pp. 239-247. doi:10.1061/(ASCE)0887-3801(2009)23:4(239)