Statistical Evaluation of Cloud Seeding Operations in Central Plateau of Iran in the 2015 Water Year

Document Type : Research Article

Authors

1 Associate Professor, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran

2 Post-Doc Researcher, Water Institute, University of Tehran, Tehran, Iran

3 Assistant Professor, School of Civil Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran

4 Professor, School of Engineering Science, College of Engineering, University of Tehran, Tehran, Iran

Abstract

Iran is located in an arid and semi-arid region and has experienced a reduction of average rainfall in recent years. This has turned the attention to the use of new methods such as cloud seeding to achieve more water resources. In this regard, cloud seeding operations have been carried out in the country since 1998. The purpose of this study was to evaluate cloud seeding projects in the 2015 water year (January, February, and March 2015) in the central region of Iran, including the provinces of Yazd, Kerman, Fars, Isfahan, and some adjacent provinces. The evaluation was performed statistically using stepwise multiple regression. Two different approaches have been used for evaluation. In the first approach, precipitation at stations located in the target area of cloud seeding operations is estimated based on the precipitation at stations in the control area using stepwise multiple regression and then taking into account a 90% confidence interval for this estimate, the effectiveness or ineffectiveness of the cloud seeding operation at each station is determined. In the second approach, the volume of precipitation in each province in the target area is estimated based on the precipitation in stations outside in the control area using stepwise multiple regression and then by considering a 90% confidence interval for this estimate, the effectiveness of cloud seeding operations on the rainfall volume of each province has been investigated. The target area in different months was selected based on the HYSPLIT model results. Due to the inconsistent spatial distribution of rain gauges in the target areas, parts of the target areas lacking enough rain gauges were excluded from further analysis. To define the boundaries of the exclusion areas, Inverse Distance Weighted (IDW) method was used to find the influence of the radius around each rain gauge. The influence radius values were selected as 93940, 89569, and 149015 m for the months of January, February, and March, respectively. Finally, the minimum value of 89569 m was selected as the influence radius. The results of both methods indicate the impact of cloud seeding operations this year in these areas. In particular, the volume of precipitation in February in all provinces located in the target area of cloud seeding operations has increased from 15 to 80 percent. Surface runoff generated from the increased precipitation due to cloud seeding were estimated by the two methods of Soil Conservation Service (SCS) and Rational method. The estimated surface runoffs generated by SCS and rational methods were 1318.5 and 1329.5 million m3, respectively. The groundwater recharge in the three months of January, February, and March is estimated as 105.3, 425.6, and 156.3 million m3, respectively. It is important to note that runoff and groundwater recharge estimations by the method used in this study are subject to high uncertainties, and the estimations can only represent the order of magnitude of impacts of cloud seeding operations, and therefore, exact numbers should not be used for water resources planning and management purposes. Further investigation in areas with more rain gauges can assist in a more accurate assessment of could seeding operations.

Keywords

Main Subjects

References

سیدحسنی، م.، مرادیان، ف.، قادر، س.، گلکار، ف. و حاتم‏پور، م.، 1397، تعیین مناطق هدف در پروژه‏های عملیاتی بارورسازی ابرها در ایران به کمک شبیه‏سازی پخش مواد باروری با استفاده از مدل پاشندگی HYSPLIT، مجله ژئوفیزیکی ایران، 12(4)، 1-30.
صفوی، ح. ر.، 1388، هیدرولوژی مهندسی، ویرایش دوم، انتشارات ارکان دانش.
مؤسسه آب دانشگاه تهران، 1396، ارزیابی پروژه‏های باروری ابرها در سال آبی 93-94 (منطقه عملیاتی ایران مرکزی).
Abedini, M. J., Nasseri, M. and Ansari, A., 2008, Cluster-based ordinary kriging of piezometric head in West Texas/New Mexico-testing of hypothesis, Journal of Hydrology, 351, 360-367.
ASCE, 2016, Guidelines to cloud seeding to augment precipitation, American Society of Civil Engineers, 2nd Edition.
DeFelice, T. P., Golden, J., Griffith, D., Woodley, W., Rosenfeld, D., Breed, D., Solak, M. and Boe, B., 2014, Extra area effects of cloud seeding-An updated assessment, Atmospheric Research, 135, 193-203.
Dennis, A. S. ,1980, Weather Modification by cloud seeding, International Geophysics Series, 24, Academic Press, New York.
Griffith, D. A, Yorty, D. and Beall, S., 2015, Target/control analyses for Santa Barbara county's operational winter cloud seeding program, The Journal of Weather Modification, 47(1)-10.
Griffith, D. A., Solak, M. E. and Yorty, D. P., 2009, 30+ Winter seasons of operational cloud seeding in Utah, WMA Journal of Weather Modification, 41, 23-37.
Griffith, D. A., Solak, M. E. and Yorty, D. P., 2011, A Winter operational cloud seeding program: Upper Gunnison river basin, Colorado, WMA Journal of Weather Modification, 43, 29-43.
Kulkarni, J. R., Morwal, S. B. and Deshpande, N. R., 2019, Rainfall enhancement in Karnataka state cloud seeding program “Varshadhare” 2017, Atmospheric Research, 219, 65-76.
Kutner, M. H., Nachtsheim, C. J. and Neter, J., 2005, Applied linear statistical models, McGraw Hill.
Manton, M. J., Peace, A. D., Kemsley, K., Kenyon, S., Speirs, J. C., Warren, L. and Denholm, J., 2017, Further analysis of a snowfall enhancement project in the Snowy Mountains of Australia, Atmospheric Research, 193, 192-203.
Montgomery, D. C., Peck, E. A. and Vining, G. G., 2012, Introduction to linear regression analysis, Fifth edition, John Wiley & Sons.
NRC, 2004, Critical issues in weather modification research. National Academies Press.
Orville, H. D., Boe, B. A., Bomar, G. W., Cotton, W. R., Marler, B. L. and Warburton, J. A., 2004, A Response by the Weather Modification Association to a National Research Council Report. Weather Modification Association.
Silverman, B. A., 2007, On the use of ratio statistics for the evaluation of operational cloud seeding programs, WMA Journal of Weather Modification, 39, 50-59.
Silverman, B. A., 2009, An Independent statistical evaluation of the Vail operational cloud seeding program, WMA Journal of Weather Modification, 41, 7-14.
Silverman, B. A., 2010, An evaluation of eleven operational cloud seeding programs in the watersheds of the Sierra Nevada Mountains, Atmospheric Research, 97, 526-539.
Weisberg, S., 2013, Applied linear regression, John Wiley & Sons.
Journal of the Earth and Space Physics
Volume 47, Issue 1
April 2021
Pages 187-203

Files

Share

How to cite

Statistics