• Dell’Angelo, A., F. Micale, and R. List, 1994: “Progetto Pioggia,” the Italian rain enhancement project. Proc. Sixth WMO Scientific Conf. on Weather Modification, Paestum, Italy, World Meteorological Organization, 11–14.

  • EMS, 1987: The Experimental Design, Phase B of Puglia Experiment. Report to TECNAGRO, 29 pp. [Available from TECNAGRO, Via T. Grossi, 6, 00184 Rome, Italy.].

  • Gabriel, K. R., 1967: The Israeli rainfall stimulation experiment: Statistical evaluation for the period 1961–1965. Proc. Fifth Berkeley Symp. on Mathematical Statistics and Probability, Vol. V, L. M. LeCam and J. Neyman, Eds., University of California Press, 91–113.

  • ——, 1991: The use of ratio statistics in rain experiments, with special reference to Puglia and Sardinia. TECNAGRO Tech. Report, TECNAGRO, Rome, Italy, 42 pp. [Available from TECNAGRO, Via T. Grossi, 6, 00184 Rome, Italy.].

  • ——, 1999: Ratio statistics for randomized experiments in precipitation stimulation. J. Appl. Meteor.,38, 290–301.

  • ——, and M. Baras, 1970: The Israeli Rainmaking Experiment 1961–67. Final statistical tables and evaluation. Department of Statistics Tech. Report, Dept. of Statistics, The Hebrew University, Jerusalem, Israel, 47 pp.

  • ——, and D. Rosenfeld, 1990: The second Israeli rainfall stimulation experiment: Analysis of precipitation on both targets. J. Appl. Meteor.,29, 1055–1067.

  • Gagin, A., and J. Neumann, 1974: Rain stimulation and cloud physics in Israel. Climate and Weather Modification, W. N. Hess, Ed., Wiley, 454–494.

  • ——, and ——, 1981: The second Israeli randomized cloud seeding experiment: Evaluation and results. J. Appl. Meteor.,20, 1301–1311.

  • Levin, Z., E. Ganor, and V. Gladstein, 1996: The effects of desert particles coated with sulfate on rain formation in the eastern Mediterranean. J. Appl. Meteor.,35, 1511–1523.

  • Nania, A., 1994: Cloud seeding and rain time intervals in experimental units. Proc., Sixth WMO Scientific Conf. on Weather Modification, Paestum, Italy, World Meteorological Organization, 27–34.

  • ——, 1996: Progetto Pioggia—La stimolazione delle precipitazioni in Italia. TECNAGRO, CD-ROM. [Available from TECNAGRO, Via T. Grossi, 6, 00184 Rome, Italy.].

  • Paccagnella, T., and G. Simonini, 1993: Interazione fra strutture orografiche e flussi troposferici nel comparto centro-occidentale della regione Basilicata (Parte integrativa). Report, Servizio Meteorologico, Regione Emilia Romagna, 54 pp. [Available from TECNAGRO, Via T. Grossi, 6, 00184 Rome, Italy.].

  • Petrondas, D. A., 1981: Two topics in permutation (re-randomization) inference: Double ratio statistics and multiple comparisons. Ph.D. thesis, University of Rochester, 366 pp. [Available from Dept. of Biostatistics, University of Rochester, Rochester, NY 14642.].

  • Scientific Committee, 1993: Progetto Pioggia: Recommendations for a five-year plan of activities 1993–1997. TECNAGRO Tech. Report, Rome, Italy, 46 pp. [Available from TECNAGRO, Via T. Grossi, 6, 00184 Rome, Italy.].

  • Shimborsky, E., 1988: Puglia, Progetto Pioggia, Phase B: The experiment design. TECNAGRO Tech. Report, TECNAGRO, Rome, Italy, 32 pp. [Available from TECNAGRO, Via T. Grossi, 6, 00184 Rome, Italy.].

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 154 154 121
PDF Downloads 30 30 7

The Rain Enhancement Experiment in Puglia, Italy: Statistical Evaluation

View More View Less
  • a Department of Physics, University of Toronto, Toronto, Ontario, Canada
  • | b Department of Statistics, University of Rochester, Rochester, New York
  • | c East Peakview Place, Englewood, Colorado
  • | d Department of Geophysics and Planetary Sciences, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Israel
  • | e Department of Meteorology, Aristotle University of Thessaloniki, Thessaloniki, Greece
© Get Permissions
Restricted access

Abstract

A randomized rain enhancement experiment was carried out during 1988–94 in the area of Bari and Canosa, Italy, on the Adriatic coast. It was commissioned by the Italian Department of Agriculture and Forestry and the region of Puglia, with TECNAGRO, a nonprofit Italian company, as overall manager, and with EMS, an Israeli company, as field operator. The original purpose was to study rain-producing weather systems in southern Italy, establish similarities with Israel, and transfer Israeli technology. The experiment was a cross-over design with two alternating target areas, a buffer in between, and two additional control areas. Seeding was by injection of silver iodide into clouds by aircraft flying near the bases of clouds along predetermined tracks upwind of the target area. The experimental units were rainy days. Based on historical rain gauge data, it was estimated that 303 rainy days were required to establish a 15% rain increase at a significance level of 0.05 and 90% power.

In 1995, TECNAGRO asked the Scientific Committee for a statistical evaluation to investigate if a seeding effect could be established before the original goal of 303 seeding days was reached. The results of the analysis of the 260 available rainy days were that no discernable seeding effect could be found. This was evident from the root double ratio (RDR) and root regression ratio (RRR), which yielded RDR − 1 = −0.083 ± 0.089 and RRR − 1 = −0.004 ± 0.057, respectively (the ± sign represents the standard error of the estimate). Based on that result, it was decided to terminate the Puglia seeding experiment.

Preliminary exploratory studies suggest that the two target areas might have been affected differently by seeding and that an apparent substantial seeding effect occurred in the Bari area under conditions of moderate precipitable water between 700 and 850 mb. If these findings are confirmed by the recommended meteorological analyses and airflow studies, a new experiment with an appropriate design might be justified.

Corresponding author address: Professor Roland List, Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.

list@atmosp.physics.utoronto.ca

Abstract

A randomized rain enhancement experiment was carried out during 1988–94 in the area of Bari and Canosa, Italy, on the Adriatic coast. It was commissioned by the Italian Department of Agriculture and Forestry and the region of Puglia, with TECNAGRO, a nonprofit Italian company, as overall manager, and with EMS, an Israeli company, as field operator. The original purpose was to study rain-producing weather systems in southern Italy, establish similarities with Israel, and transfer Israeli technology. The experiment was a cross-over design with two alternating target areas, a buffer in between, and two additional control areas. Seeding was by injection of silver iodide into clouds by aircraft flying near the bases of clouds along predetermined tracks upwind of the target area. The experimental units were rainy days. Based on historical rain gauge data, it was estimated that 303 rainy days were required to establish a 15% rain increase at a significance level of 0.05 and 90% power.

In 1995, TECNAGRO asked the Scientific Committee for a statistical evaluation to investigate if a seeding effect could be established before the original goal of 303 seeding days was reached. The results of the analysis of the 260 available rainy days were that no discernable seeding effect could be found. This was evident from the root double ratio (RDR) and root regression ratio (RRR), which yielded RDR − 1 = −0.083 ± 0.089 and RRR − 1 = −0.004 ± 0.057, respectively (the ± sign represents the standard error of the estimate). Based on that result, it was decided to terminate the Puglia seeding experiment.

Preliminary exploratory studies suggest that the two target areas might have been affected differently by seeding and that an apparent substantial seeding effect occurred in the Bari area under conditions of moderate precipitable water between 700 and 850 mb. If these findings are confirmed by the recommended meteorological analyses and airflow studies, a new experiment with an appropriate design might be justified.

Corresponding author address: Professor Roland List, Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.

list@atmosp.physics.utoronto.ca

Save