The Alberta Hail Project was a

research Research is creative and systematic work undertaken to increase the stock of knowledge. It involves the collection, organization, and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness to ...

project sponsored by the Alberta Research Council and

Environment Canada Environment and Climate Change Canada (ECCC; )Environment and Climate Change Canada is the applied title under the Federal Identity Program; the legal title is Department of the Environment (). is the Ministry (government department), department ...

to study hailstorm physics and dynamics in order to design and test means for suppressing

hail Hail is a form of solid Precipitation (meteorology), precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailsto ...

. It ran from 1956 until 1985. The main instrument in this research was an

S-band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the convention ...

circularly polarized

weather radar A weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation (meteorology), precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern w ...

located at the

Red Deer The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or Hart (deer), hart, and a female is called a doe or hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Ir ...

Industrial Airport in central

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. A vast amount of data was collected from several other platforms to conduct research into precipitation mechanisms, severe storm development, hail suppression,

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...

and

microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...

propagation. Numerous researchers have used the dataset and during the period 1990 to 1994, 23 publications appeared in journals and conferences, as well as 4 scientific reports were prepared. These papers have included

radar meteorology A weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly puls ...

cloud physics Cloud physics is the study of the physical processes that lead to the formation, growth and precipitation of atmospheric clouds. These aerosols are found in the troposphere, stratosphere, and mesosphere, which collectively make up the greatest p ...

, hydrology/hydro

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

computer science Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...

, instrumentation, synoptic weather, dynamic and

mesoscale meteorology Mesoscale meteorology is the study of weather systems and processes at horizontal scales of approximately to several hundred kilometres. It is smaller than synoptic scale meteorology, synoptic-scale systems (1,000 km or larger) but larger than Mi ...

Description

The project area covered 33,700 km² and was centred on the Penhold radar site located near the Red Deer Airport (). The program had different ways of evaluating the atmospheric conditions for hail and its detection. Each spring, approximately 20,000 farmers in the project area would receive cards to record any event of hail, including its size. On days with hail, between 10 % and 20 % of the farmers reported, an average of one observer per 16–32 km². Telephone surveys were also conducted, resulting in observation densities as high as one report per 3 square kilometers. As a result, it is believed that only a very small percentage of hail reaching the surface went undetected. For the duration of the project, six categories were specified to size the observed hailstones conveniently: diameters less than 0.4 cm, 0.4–1.2 cm, 1.3–2.0 cm; 2.1–3.2 cm, 3.3–5.2 cm, and larger than 5.2 cm. Radiosondes were released from Penhold at 1715 local time (2315 UTC). Data were used to evaluate the atmospheric conditions on hail days within 3 h (i.e., between 1415 and 2015 LT) and 100 km from the sounding site. A few of these proximity soundings had to be excluded because of missing data or because they were modified by precipitation or a thunderstorm

outflow boundary An outflow boundary, also known as a gust front, is a storm-scale or mesoscale meteorology, mesoscale boundary separating thunderstorm-cooled air (Outflow (meteorology), outflow) from the surrounding air; similar in effect to a cold front, with ...

. In addition to upper-air sounding data, the surface temperature and dewpoint (representative of the storm's inflow) were obtained from a

mesonet In meteorology and climatology, a mesonet, portmanteau of mesoscale network, is a network of automated weather and, often also including environmental monitoring stations, designed to observe mesoscale meteorological phenomena and/or microclima ...

work. The radar would be used to detect not only the intensity of the precipitation by its

reflectivity The reflectance of the surface of a material is its effectiveness in Reflection (physics), reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the respon ...

, but the type of

hydrometeor In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwealth ...

s with the

circular polarization In electrodynamics, circular polarization of an electromagnetic wave is a polarization state in which, at each point, the electromagnetic field of the wave has a constant magnitude and is rotating at a constant rate in a plane perpendicular to ...

. These would be correlated with the surface observations to study the structure of the thunderstorms leading to hail formation. Furthermore, at certain times there would be aircraft flight in and around convective areas to gather further information on the atmospheric conditions and sample the clouds. Observations were also made b
sampling vehicles
The vehicles were outfitted with various meteorological instrumentation and hail catching apparatus. They were directed into suspected thunderstorm hail regions by a controller at the radar site. The controller communicated with the vehicles by radio.

References

External links

The Alberta Hail Project Meteorological and Barge-Humphries Radar Archive
Severe weather and convection Hail Mesoscale meteorology Meteorology research and field projects Weather modification in North America Storm chasing {{climate-stub