J.S. Marshall Radar Observatory
Encyclopedia
The J.S. Marshall Radar Observatory (or MRO) is a McGill University
facility in Sainte-Anne-de-Bellevue, Quebec
housing several weather radar
s and other meteorological sensors, many of them running around the clock. It is one of the components of the McGill Atmospheric and Oceanic Sciences
department where students in remote sensing perform their research. Furthermore, the main radar is part of the Canadian weather radar network
, on a contract with the Meteorological Service of Canada
, as well as a research device.
In 1943, "Project Stormy Weather" was assigned to J.S. Marshall by the Department of National Defence
. The aim was to find a use for noise in radar echoes that had proved to be from weather. Marshall and his doctoral student Walter Palmer later received recognition for their work on the drop size distribution in mid-latitude rain that led to the rain rate relation to radar reflectivity
(Z-R relation). Following World War II
, Marshall and R.H. Douglas formed the "Stormy Weather Group" at McGill University and continued their work.
Different radars were used by the Stormy Weather Group to research the characteristics of precipitation at Dawson College
, continuing the tradition of meteorology at McGill. It was decided to build a new facility in 1968 in Sainte-Anne-de-Bellevue, on the western tip of Montreal Island and to transfer research activity from Dawson College to this facility. This new observatory was later renamed the J.S. Marshall Radar Observatory in honor of its founder.
A 10 cm wavelength Doppler and dual-polarization radar
built in 1968 and used for weather surveillance around the Montreal
, Canada area. It is part of the Canadian weather radar network
, used by the local weather office to monitor weather in real time for a variety of applications, from severe weather detection to sewer flow forecasting.
Characteristics :
As it is a research as well as an operational radar, the large amount of data accumulated is studied for further development in radar hardware and software capabilities. The data are correlated with the other instruments in related research.
McGill University
Mohammed Fathy is a public research university located in Montreal, Quebec, Canada. The university bears the name of James McGill, a prominent Montreal merchant from Glasgow, Scotland, whose bequest formed the beginning of the university...
facility in Sainte-Anne-de-Bellevue, Quebec
Sainte-Anne-de-Bellevue, Quebec
Sainte-Anne-de-Bellevue is a town located at the western tip of the Island of Montreal in southwestern Quebec, Canada. It is the second oldest community in Montreal's West Island, having been founded as a parish in 1703...
housing several weather radar
Weather radar
Weather radar, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, estimate its type . Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the...
s and other meteorological sensors, many of them running around the clock. It is one of the components of the McGill Atmospheric and Oceanic Sciences
McGill Atmospheric and Oceanic Sciences
The Department of Atmospheric and Oceanic Sciences of McGill University is the largest university atmospheric-oceanic sciences group in Canada. It currently has 11 Faculty and 6 Associate Faculty members, 5 support staff, 14 research associates and postdoctoral fellows, and 31 graduate students. It...
department where students in remote sensing perform their research. Furthermore, the main radar is part of the Canadian weather radar network
Canadian weather radar network
The Canadian weather radar network consists of 31 weather radars spanning Canada's most populated regions. Their primary purpose is the early detection of precipitation, its motion and the threat it poses to life and property...
, on a contract with the Meteorological Service of Canada
Meteorological Service of Canada
The Meteorological Service of Canada , also known as "The Canadian Weather Service", is a division of Environment Canada, which primarily provides public meteorological information and weather forecasts and warnings of severe weather and other environmental hazards...
, as well as a research device.
Purpose
The main focus of the MRO is teaching and research. The group upgrades and designs radars, develops new ways to process the radar signals and use the resulting data, and performs research on the physics of weather events and their prediction. Results of the research are published in scientific journals and transferred for use by the weather office.History
In 1862, a first Weather Observatory was built by McGill University. The instruments were donated by Dr. Charles Smallwood (MD), who had personally taken weather data with them since 1840. This station became one of the first in the weather station network set up after the telegraph became ubiquitous.In 1943, "Project Stormy Weather" was assigned to J.S. Marshall by the Department of National Defence
Department of National Defence (Canada)
The Department of National Defence , frequently referred to by its acronym DND, is the department within the government of Canada with responsibility for all matters concerning the defence of Canada...
. The aim was to find a use for noise in radar echoes that had proved to be from weather. Marshall and his doctoral student Walter Palmer later received recognition for their work on the drop size distribution in mid-latitude rain that led to the rain rate relation to radar reflectivity
Reflectivity
In optics and photometry, reflectivity is the fraction of incident radiation reflected by a surface. In general it must be treated as a directional property that is a function of the reflected direction, the incident direction, and the incident wavelength...
(Z-R relation). Following World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, Marshall and R.H. Douglas formed the "Stormy Weather Group" at McGill University and continued their work.
Different radars were used by the Stormy Weather Group to research the characteristics of precipitation at Dawson College
Dawson College
Dawson College was the first English CEGEP and is located in Westmount, just west of downtown Montreal, Quebec, Canada. Dawson College is located near the heart of downtown Montreal in a former nunnery on 4.85 hectares of green space...
, continuing the tradition of meteorology at McGill. It was decided to build a new facility in 1968 in Sainte-Anne-de-Bellevue, on the western tip of Montreal Island and to transfer research activity from Dawson College to this facility. This new observatory was later renamed the J.S. Marshall Radar Observatory in honor of its founder.
Main instrument
Weather radar
Weather radar, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, estimate its type . Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the...
built in 1968 and used for weather surveillance around the Montreal
Montreal
Montreal is a city in Canada. It is the largest city in the province of Quebec, the second-largest city in Canada and the seventh largest in North America...
, Canada area. It is part of the Canadian weather radar network
Canadian weather radar network
The Canadian weather radar network consists of 31 weather radars spanning Canada's most populated regions. Their primary purpose is the early detection of precipitation, its motion and the threat it poses to life and property...
, used by the local weather office to monitor weather in real time for a variety of applications, from severe weather detection to sewer flow forecasting.
Characteristics :
- Its ICAO calling identifier is CWMN.
- Its coordinates are 45°25′26.76"N 73°56′14.64"W, at 50 m above sea level.
- It has a large 9 meter (30 foot) diameter antenna transmitting impulses from a klystronKlystronA klystron is a specialized linear-beam vacuum tube . Klystrons are used as amplifiers at microwave and radio frequencies to produce both low-power reference signals for superheterodyne radar receivers and to produce high-power carrier waves for communications and the driving force for modern...
. - Its tower is 25 m high.
- It scans the atmosphere on 24 angles from 0.5 to 34.4 degrees above the horizon in 5 minutes.
- It was originally recording only reflectivitiesReflectivityIn optics and photometry, reflectivity is the fraction of incident radiation reflected by a surface. In general it must be treated as a directional property that is a function of the reflected direction, the incident direction, and the incident wavelength...
, giving position and intensity of precipitationPrecipitation (meteorology)In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
. In 1992, it was upgraded to treat Doppler data and thus estimate the motion of the drops. It was upgraded again in 1999 with a dual polarization capability which allows direct identification of the type of precipitation (rain, snow, hail, etc...).
As it is a research as well as an operational radar, the large amount of data accumulated is studied for further development in radar hardware and software capabilities. The data are correlated with the other instruments in related research.
Other instruments
Many other devices are operated by the MRO at the site or in other locations. These varies according to the research interests pursued. Some of them are or have been :- UHF Wind profilerWind profilerA wind profiler is a type of weather observing equipment that uses radar or sound waves to detect the wind speed and direction at various elevations above the ground. Readings are made at each kilometer above sea level, up to the extent of the troposphere...
- Bistatic radars
- X-band (3 centimeter wavelength) vertical pointing radar
- CeilometerCeilometerA ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere.-Optical Drum Ceilometer:...