Hong Kong weather

Eye on the storms: weather forecasters launch HK$9 million typhoon tracking system

Officials unveil technology featuring dropsonde devices that are dropped from aircraft at high altitude and expected to enhance data collection

PUBLISHED : Friday, 03 March, 2017, 9:50pm
UPDATED : Friday, 03 March, 2017, 11:49pm

Hong Kong’s weather forecasters are hoping to improve accuracy in predicting and tracking typhoons this year with storm-chasing aircraft featuring new technology.

The Observatory and Government Flying Service (GFS) on Friday unveiled the dropsonde system, which allows first-hand meteorological data collection using a cylindrical device that is dropped into a storm from aircraft flying at high altitude.

The dropsonde, fitted with sensors, a radio transmitter and GPS antenna, is intended to help meteorologists collect more precise data to determine the location and intensity of a storm – while also keeping aircraft at a safe distance above the storm.

The government began trying out the technology in September last year and has used it four times in total.

Watch: Observatory shows the new system

“We can get weather information [from top to bottom] when the dropsonde is falling. That would help us understand the 3D structure of the storm and be useful in analysis,” said Sharon Lau Sum-yee, assistant director at the Observatory.

Hong Kong’s weather forecasters are under constant pressure to justify their decisions to issue the No 8 storm signal when typhoons get too close, shutting down the city.

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The Observatory came under strong criticism in July 2015 for issuing the signal when Typhoon Linfa was said to be threatening despite relatively calm weather conditions. Forecasters defended their predictions, based on data collected by a government plane that flew into the centre of the storm and detected hurricane-force winds.

GFS controller Captain Michael Chan Chi-pui noted that the new technology would also make it safer for aircraft crew.

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“As the aircraft is at 35,000 feet up in the sky and above the typhoon, the risk is much lower,” Chan said.

In the past, GFS pilots had to fly into storms with sensors fitted on the wings of their planes.

As the aircraft is at 35,000 feet up in the sky and above the typhoon, the risk is much lower
Captain Michael Chan Chi-pui, GFS controller

“For the old system, we could only collect weather information at certain layers [of the atmosphere],” Lau added.

Captain Eric Leung Man-chiu, a senior GFS pilot qualified to fly planes with the new technology, recalled the risks of the past.

“Now we don’t have to enter the clouds. If we did that it could lead to icing, which is the biggest enemy of aircraft,” he said.

The dropsonde system will be used if a typhoon comes within 300 to 500 kilometres of Hong Kong’s centre.

The GFS has 11 pilots and 11 crew trained and ready to use for the coming typhoon season.

The dropsonde system hardware, from a Finnish manufacturer, cost taxpayers HK$9 million.

Each dropsonde costs HK$6,000 and is not reusable. For each storm-monitoring mission, up to 10 devices must be used to gather data.