Part I of this document is a summary of reports of weather INTRODUCTION This report presents information on domestic and selected foreign weather modification activities for CY 1975. In prior years, similar information was published in three separate document series: (a) a summary of research and operational projects reported under Public Law 92-205 (National Oceanic and Atmospheric Administration 1975), (b) an annual summary report on weather modification activities, foreign and domestic (National Oceanic and Atmospheric Administration 1974), and (c) an annual report on Federal programs in atmospheric sciences (Interdepartmental Committee for Atmospheric Sciences 1975). Part I of this report is a continuation of the series, type (a). Publication of the series, type (b) has ended, but most of the subject areas are now to be included in part II of this report in less detail than previously given. Reports of type (c) will continue to be published and are considered to be complementary to the information given herein. Part I: Summary of Weather Modification Reporting BACKGROUND On December 18, 1971, Congress enacted Public Law 92-205, requiring that all nonfederally sponsored weather modification activities in the United States be reported to the Secretary of Commerce and that summaries of these activities be published periodically. The National Oceanic and Atmospheric Administration (NOAA) has administered, on behalf of the Secretary, a weather modification reporting program that became effective on November 1, 1972. Since November 1, 1973, Federal agencies have reported their activities to NOAA under interagency agreement. Accordingly, NOAA's reporting system provides a central source of information on weather modification projects carried out in the United States and its territories. The reporting procedures were amended on February 15, 1974, to cover safety and environmental aspects of field activities and to consider possible interference with Federal research projects. Copies of the reporting law, reporting rules and forms, the amendments, and the Federal reporting procedures are contained in a summary report by Charak and DiGiulian (1974). The rules were also amended in 1976; copies of the complete rules and reporting forms are attached at the end of this report. Requests for information on the reporting program should be directed to: Environmental Modification Office (EM5) NOAA 6010 Executive Blvd. Rockville, Md. 20852 This summary includes both nonfederal and Federally sponsored weather modification activities carried out in CY 1975. The report describes the projects that were initiated during 1975 and the projects active during the year but started prior to January 1, 1975. It includes analyses of data on project purpose, sponsors, operators, target locations, target areas; and modification techniques, apparatus, agents, and dispersing rates. Additional information is provided on modification days, missions, duration of seeding activities, and amounts of seeding agents. Also included is a brief discussion of reported information on operational safeguards and environmental impact associated with weather modification activities. A comparison of information reported in CY 1974 and 1975 is presented as well. DATA BASE Initial, interim, and final reports submitted to NOAA provide the data base for this summary of weather modification activities. Each activity is assigned a NOAA file number upon receipt of an initial report from a project official; appendix A lists 85 reports analyzed herein for activities in CY 1975. An interim report is required on October 1st* of each year unless the project was terminated before that date, and a final report is due on completion of a project. A weather modification project is considered active until a final report is filed with NOAA. All reports are reviewed and requests are sent to the operators when the data are incomplete; replies are usually prompt. To date, experience with the reporting program shows that the information most often requiring a follow-up request concerns sponsor and operator identification, target area maps, aircraft used, dispersal rates of modification agents, date on which final weather modification activity occurred, and signature. SUMMARY OF DATA The reported information has been grouped into several categories for convenience in analyzing the data. These categories are discussed in the following sections. Number of Activities Inspection of the 85 weather modification projects recorded in NOAA's reporting program (appendix A) shows that 12 projects were completed early in the year, but later 12 similar projects were reinstated at the same locations. Activity numbers 75-121F and 75-122F (using aircraft and groundbased techniques, respectively, at Elmendorf AFB, Alaska) were replaced late in the year by number 76-177F (ground-based technique). The other paired projects are 74-114 and 75-168, 75-115 and 76-178, 75-118 and 76-171, 75-120 and 76-186, 75-123F and 76-176F, 75-124 and 75-164, 75-125 and 76–197, 75-126 and 76-175, 75-128 and 76-174, 75-129 and 76-173, and 75-134 and 75-169. Accordingly, activities were carried out at only 72 separate locations in CY 1975. Appendix A also shows that 10 activities were continued from previous years and did not terminate in 1975. The continuing projects are 73-010, 73-014, 73-015, 73-029, 74-062 through 74-066, and 74-077. For these activities, operators are required to file interim reports and to update their initial reports if changes occur. A final report is due upon completion or if a long delay is expected. Table 1 gives a breakdown of the 72 non duplicative projects to be summarized in this report. Note that nonduplicative data from all 85 reports submitted to NOAA are included in the analyses that follow. * Now January 1st (see rules and forms attached). Table 1.--Active, nonduplicative weather modification Nonfederal projects Federally sponsored projects Projects active on January 1, 1975 Projects active on December 31, 1975 Projects active on January 1 and December 31, 1975 Projects completed in CY 1975 58 14 35 26 10 37 46 Operators Table 2 indicates the number of projects or activities carried out by various types of operators during the reporting period. One commercial weather modification firm undertook projects at 17 of the 72 locations. Another company carried out seven separate projects, and a third concern was responsible for five. Federal operators included NOAA, the National Science Foundation, the Department of Defense, and the Bureau of Reclamation. The various types of sponsors of the reported activities and the corresponding number of their projects are given in table 3. Some activities have multiple sponsors, particularly at airports where several airlines may enter into joint funding for fog dispersal. The sponsors of the Federal projects were the Air Force, Army, Navy, Bureau of Reclamation Municipal districts generally provided water resources to large areas in a State. In several States, a few counties united to form a county or community association and sponsor activities that were supported by local or voluntary donations. An analysis of the reported activities shows that four objectives were specified: precipitation (rainfall and snowfall) increase, fog dispersal, hail decrease, and weather modification research. Federal research included precipitation management, fog clearance and prevention, lightning suppression, tests of seeding agents and apparatus, and studies of downwind effects. Table 4 lists the number of activities according to purpose and sponsor. The total (88) is larger than the number of nonduplicative projects (72) because some projects have two purposes (e.g., rain increase and hail decrease). Table 4 shows that, of the 88 purposes, 44 were directed toward increasing precipitation (chiefly rain), 15 to modifying fog (mostly cold fog), and 14 to decreasing hailfall. Of the 15 research activities, 12 were Federally |