cloudsR Documentation

Cloud Seeding Data


Data from an experiment investigating the use of massive amounts of silver iodide (100 to 1000 grams per cloud) in cloud seeding to increase rainfall.




A data frame with 24 observations on the following 7 variables.


a factor indicating whether seeding action occured (no or yes).


number of days after the first day of the experiment.


suitability criterion.


the percentage cloud cover in the experimental area, measured using radar.


the total rainfall in the target area one hour before seeding (in cubic metres times 1e+8).


a factor showing whether the radar echo was moving or stationary.


the amount of rain in cubic metres times 1e+8.


Weather modification, or cloud seeding, is the treatment of individual clouds or storm systems with various inorganic and organic materials in the hope of achieving an increase in rainfall. Introduction of such material into a cloud that contains supercooled water, that is, liquid water colder than zero Celsius, has the aim of inducing freezing, with the consequent ice particles growing at the expense of liquid droplets and becoming heavy enough to fall as rain from clouds that otherwise would produce none.

The data available in cloud were collected in the summer of 1975 from an experiment to investigate the use of massive amounts of silver iodide 100 to 1000 grams per cloud) in cloud seeding to increase rainfall. In the experiment, which was conducted in an area of Florida, 24 days were judged suitable for seeding on the basis that a measured suitability criterion (SNE).


W. L. Woodley, J. Simpson, R. Biondini and J. Berkeley (1977), Rainfall results 1970-75: Florida area cumulus experiment. Science 195, 735–742.

R. D. Cook and S. Weisberg (1980), Characterizations of an empirical influence function for detecting influential cases in regression. Technometrics 22, 495–508.


  data("clouds", package = "HSAUR")
  layout(matrix(1:2, nrow = 2))
  boxplot(rainfall ~ seeding, data = clouds, ylab = "Rainfall")
  boxplot(rainfall ~ echomotion, data = clouds, ylab = "Rainfall")