Why has the Perth radar been moved?
The original Perth radar was commissioned in the mid eighties, and since that time there has been a dramatic change in the skyline of the Perth CBD. This change is likely to continue in the future, with more high rise buildings being developed. This could potentially lead to an increase in radar shadows (which were already evident on the radar) due to the proximity of high rise buildings. It was therefore not considered wise to leave the radar in the CBD.
The new location is in land designated bush forever, which should mean no future developments will impact on the radar.
The move means I can't see rain in my area any more.
The new Perth weather radar near Serpentine located about 50 km south of the Perth CBD will improve coverage over the southwest of the state including Bunbury, Busselton and Margaret River and will help people in Perth to see approaching winter rainfall to the southwest earlier than they previously could. Using the latest technology the radar will actually improve the ability to detect rainfall in and to the north of Perth including the Wheat Belt.
I am concerned that this new radar is not as effective in showing rain as the old radar.
The images below show the differences between the 2 radars for a number of situations. Notice in particular the greater sensitivity of the Serpentine radar, especially for precipitation over western parts of the Central Wheat Belt and northwestern parts of the Great Southern.
The greater accuracy of the radar will mean that rainfall will appear to be heavier compared to the previous Perth radar. This is best demonstrated in the series of comparison radar images between the new radar and the previous one at Kings Park during testing in the first part of 2010. Notice the higher rainfall rates on the new radar, including for areas of the Central Wheat Belt and the Great Southern. This is particularly noticeable on 22 March when intense rainfall and hail to 6 cm occurred in Perth causing more than one billion dollars in damage.
|Heavy showers and thunderstorms to the south of Perth. Serpentine radar shows higher radar reflectivities, particularly to the southeast near Wandering.|
|Thunderstorms to the southeast of Perth. In addition to showing higher radar reflectivities, this also shows the greater range that Serpentine has towards Albany.|
|Heavy showers and thunderstorms northeast of Perth. It appears that there is little loss of signal in detecting rainfall to the north and northeast of Perth, even though Serpentine is located south of Perth. Although obviously the 256 km range does not extend as far on the display.|
|Perth severe hailstorm and heavy rainfall. Despite reports of 6cm hail Kings Park radar only showed moderate to heavy rainfall rates in the yellow to orange range, whereas Serpentine showed very heavy rainfall rates.|
|Rainband over radar. There is less attenuation (loss of radar signal) with the rainband over the radar.|
|In the image above a cloud band moved over Perth and produced nearly 15mm of rain, and yet the Perth radar failed to show echoes beyond the first 2 blue colours. Perth radar also failed to show echoes near Goomalling.|