clouds                 package:HSAUR                 R Documentation

_C_l_o_u_d _S_e_e_d_i_n_g _D_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

     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.

_U_s_a_g_e:

     data("clouds")

_F_o_r_m_a_t:

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

     _s_e_e_d_i_n_g a factor indicating whether seeding action occured ('no'
          or 'yes').

     _t_i_m_e number of days after the first day of the experiment.

     _s_n_e suitability criterion.

     _c_l_o_u_d_c_o_v_e_r the percentage cloud cover in the experimental area,
          measured using radar.

     _p_r_e_w_e_t_n_e_s_s the total rainfall in the target area one hour before
          seeding (in cubic metres times '1e+8').

     _e_c_h_o_m_o_t_i_o_n a factor showing whether the radar echo was 'moving' or
          'stationary'.

     _r_a_i_n_f_a_l_l the amount of rain in cubic metres times '1e+8'.

_D_e_t_a_i_l_s:

     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').

_S_o_u_r_c_e:

     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.

_E_x_a_m_p_l_e_s:

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

