The KNMI-mast Cabauw is a 213-metre (699') high guyed mast for meteorological measurements at Cabauw, the Netherlands. In 1972 at Cabauw (06348) a 213 metre (699') high mast was specifically built for meteorological research to establish relations between the state of the atmospheric boundary layer (ABL), land surface conditions and the general weather situation for all seasons. The Cabauw mast is located in the western part of the Netherlands (51.971 °N, 4.927 °E) in a polder 0.7 metres (28") below average sealevel. This site was chosen, because it is rather representative for this part of the Netherlands and because only minor landscape developments were planned in this region. However, significant changes are the removal of the trees along a road east of the mast in 1975, and the building of houses in the village of Lopik east of the mast in more recent years.
The North Sea is more than 50 km (30 miles) away to the WNW. The nearby region is agricultural, and surface elevation changes are at most a few metres (yards) over 20 km (12 miles). Within 40 km (25 miles) radius there are four major synoptic weather stations, among which is the regular radiosonde station at De Bilt (06260), ensuring a permanent supporting mesoscale network. Near the mast, the terrain is open pasture for at least 400 metres (yards) in all directions, and in the WSW direction for 2 km (1¼ miles). Farther away, the landscape is generally very open in the West sector, while the distant East sector is rather rough (windbreaks, orchards, low houses).
The distant North and South sectors are mixed landscapes, much pasture and some windbreaks. So the highest mast levels have in all directions a long fetch of landscape roughness which is usefully similar to the roughness observed in the lower surface layer. On the mast itself no undisturbed measurements can be made below 20 metres (60'). Therefore, auxiliary 20 metre (60') masts are installed to the SE and the NW at sufficient distance from the mast foot building. South of the mast is a well-kept observation field for micrometeorological observations, including soil heat flux, soil temperatures and various radiation measurements; north of the mast is a spare observation field. The soil consists of 0.6 metres (2') of river-clay, overlying a thick layer of peat. The water table is about 1 metres (3') below the surface, but can be higher during wet periods.
The mast is a closed cylinder of 2 metres (6') diameter, with an elevator inside. It is guyed at four levels, and carries booms at 20 metre (60') intervals in three directions. The 9.4 metre (30') booms can be swung up hydraulically, so that instruments at their ends can be handled from an upper balcony; this swivelling mounting allows much longer booms than the customary sideways-sliding construction. Permanent signal cables in the boom tubes run through the hollow swivel axis, so during boom motion they are only torsion-deformed, a more endurable load than bending. Built around the mast foot is a 200 m2 (2000 sq. ft.) streamlined building for registration and maintenance purposes. On top of the mast, a compact weather radar was installed in 2007, measuring precipitation up to a radius of 60 km (40 miles) around the mast.
ReferencesEdit
In Higher Spheres; 40 years of observations at the Cabauw Site. Wim Monna and Fred Bosveld, 2013. KNMI-Publication 232
External linksEdit
Diagram at skyscraperpage.com.
.
.
Real-time weather radar measurement from the mast top.
knmi, mast, cabauw, metre, high, guyed, mast, meteorological, measurements, cabauw, netherlands, 1972, cabauw, 06348, metre, high, mast, specifically, built, meteorological, research, establish, relations, between, state, atmospheric, boundary, layer, land, su. The KNMI mast Cabauw is a 213 metre 699 high guyed mast for meteorological measurements at Cabauw the Netherlands In 1972 at Cabauw 06348 a 213 metre 699 high mast was specifically built for meteorological research to establish relations between the state of the atmospheric boundary layer ABL land surface conditions and the general weather situation for all seasons The Cabauw mast is located in the western part of the Netherlands 51 971 N 4 927 E in a polder 0 7 metres 28 below average sealevel This site was chosen because it is rather representative for this part of the Netherlands and because only minor landscape developments were planned in this region However significant changes are the removal of the trees along a road east of the mast in 1975 and the building of houses in the village of Lopik east of the mast in more recent years KNMI mast CabauwKNMI mast CabauwGeneral informationStatusCompletedTypePartially guyed towerLocationCabauw NetherlandsCoordinates51 58 12 00 N 4 55 34 48 E 51 9700000 N 4 9262444 E 51 9700000 4 9262444Completed1972Height213 m 699 ft The North Sea is more than 50 km 30 miles away to the WNW The nearby region is agricultural and surface elevation changes are at most a few metres yards over 20 km 12 miles Within 40 km 25 miles radius there are four major synoptic weather stations among which is the regular radiosonde station at De Bilt 06260 ensuring a permanent supporting mesoscale network Near the mast the terrain is open pasture for at least 400 metres yards in all directions and in the WSW direction for 2 km 1 miles Farther away the landscape is generally very open in the West sector while the distant East sector is rather rough windbreaks orchards low houses The distant North and South sectors are mixed landscapes much pasture and some windbreaks So the highest mast levels have in all directions a long fetch of landscape roughness which is usefully similar to the roughness observed in the lower surface layer On the mast itself no undisturbed measurements can be made below 20 metres 60 Therefore auxiliary 20 metre 60 masts are installed to the SE and the NW at sufficient distance from the mast foot building South of the mast is a well kept observation field for micrometeorological observations including soil heat flux soil temperatures and various radiation measurements north of the mast is a spare observation field The soil consists of 0 6 metres 2 of river clay overlying a thick layer of peat The water table is about 1 metres 3 below the surface but can be higher during wet periods The mast is a closed cylinder of 2 metres 6 diameter with an elevator inside It is guyed at four levels and carries booms at 20 metre 60 intervals in three directions The 9 4 metre 30 booms can be swung up hydraulically so that instruments at their ends can be handled from an upper balcony this swivelling mounting allows much longer booms than the customary sideways sliding construction Permanent signal cables in the boom tubes run through the hollow swivel axis so during boom motion they are only torsion deformed a more endurable load than bending Built around the mast foot is a 200 m2 2000 sq ft streamlined building for registration and maintenance purposes On top of the mast a compact weather radar was installed in 2007 measuring precipitation up to a radius of 60 km 40 miles around the mast References EditIn Higher Spheres 40 years of observations at the Cabauw Site Wim Monna and Fred Bosveld 2013 KNMI Publication 232External links EditDiagram at skyscraperpage com Description at KNMI Current meterorological data Real time weather radar measurement from the mast top See also EditList of masts Retrieved from https en wikipedia org w index php title KNMI mast Cabauw amp oldid 1165970929, wikipedia, wiki, book, books, library,
