WC-130 Hercules
The WC-130 Hercules is a high-wing, medium-range aircraft flown by the Air Force Reserve Command (AFRC) for weather reconnaissance missions. The WC-130 is a modified version of the C-130 transport configured with computerized weather instrumentation for penetration of severe storms to obtain data on storm’s movements, dimensions and intensity. The WC-130B became operational in 1959, the E model in 1962, followed by the H model in 1964. Only the H model is currently in operation.
The WC-130 provides vital tropical cyclone forecasting information. It penetrates tropical cyclones and hurricanes at altitudes ranging from 500 to 10,000 feet (151.7 to 3033.3 meters) above the ocean surface depending upon the intensity of the storm. The aircraft’s most important function is to collect high density/high accuracy weather data from within the storm’s environment. This includes penetration of the center (eye) of the storm. This vital information is instantly relayed by satellite to the National Hurricane Center to aid in the accurate forecasting of hurricane movement and intensity.
The WC-130 is flown exclusively from Keesler Air Force Base, MS, by the 53rd Weather Reconnaissance Squadron, an AFRC organization known as the Hurricane Hunters. Its hurricane reconnaissance area includes the Atlantic Ocean, Caribbean Sea, Gulf of Mexico and central Pacific Ocean areas.
Project Popeye
Weather modification is a technology once embraced by the U.S. military as a tool to help both wartime and peacetime missions. However, interest in the ability to modify weather has waned over recent years and is now nearly non-existent.
One method that was tried but later abandoned by the military was the use of aircraft dry ice seeding to dissipate cold fog. In the late 1960s and early 1970s, specially configured WC-130 aircraft were equipped with a dry ice crusher and dispenser. On a typical mission such aircraft would fly a seeding pattern consisting of between five and 30 parallel lines, each five to six miles long and 0.5 to 1.5 miles apart. This pattern would be flown just above the fog at a distance between 45 and 60 minutes upwind of the area where clearing was desired, with the machine generally dispensing 15 pounds of crushed dry ice per minute. The hole then, hopefully, drifts over the desired area at the desired time. The return on the investment in these operations was significant; during the winter of 1969–70, fog dispersal operations in the United States via this method cost $80,000 but saved $900,000. As weather modification became discredited in the mid-1970s, this method was abandoned.
With the onset of the Vietnam War, operational interest in modifying weather to support combat operations increased, ultimately leading to a multiservice effort called Project Popeye. Its goal was to flood supply routes used by the North Vietnamese into South Vietnam by seeding clouds in the area. Between 1949 and 1978 China Lake developed concepts, techniques, and hardware that were successfully used in hurricane abatement, fog control, and drought relief. Military application of this technique was demonstrated in 1966 when Project Popeye was conducted to enhance rainfall to help interdict traffic on the Ho Chi Minh Trail.
The Air Force continued its attempts at weather modification, flying rain-making missions during six southwest monsoon seasons before the project ended on July 5, 1972. Aircraft dropped photoflash cartridges inside certain clouds, relying on the release of silver iodide or lead iodide in the updraft to trigger the release of moisture. The annual cost of the effort was roughly $3.6 million, including the operation and maintenance of three Lockheed WC–130s and two McDonnell Douglas RF–4Cs, purchase of seeding materials, and pay for the people involved.
It proved impossible, however, to determine the amount of additional rainfall caused by cloud-seeding and thus justify the recurring outlay. The Defense Intelligence Agency estimated that seeding increased rainfall “in limited areas up to 30 percent above that predicted for the existing conditions,” but this figure admittedly was the result of “empirical and theoretical techniques based on units expended and the physical properties of the air mass seeded”—in short, a scientific guess. Sensor data showed only that the enemy consistently experienced difficulty keeping traffic moving through the monsoon rains, a normal problem for that time of year.
From time to time, especially during 1971, tropical storms either intensified the downpour associated with the southwest monsoon or extended the rainy season beyond its anticipated close. Atmospheric conditions over either the Indian Ocean or the South China Sea, rather than cloud seeding over southern Laos, spawned these typhoons. Ironically, typhoon-induced rains interfered with cloud seeding, cooling the earth and preventing the updrafts of heated air that were essential to the project.
When this effort was exposed, however, the military endured tremendous pressure and criticism, especially from Congress. Within five years of the negative publicity, US military weather modification research had ceased. The ENMOD Treaty prohibited weather modification from occurring over a large area.
