Local residents are all too familiar with the Hong Kong Observatory's weather bulletins on tropical cyclones, and hearing that the storm has "intensified" has become part of the local vernacular.
The best way to understand a storm's intensity and predict its path is to get close enough to study it. The observatory works with the local aviation community and shipping companies to collect meteorological data using planes and ships that are specially-equipped to do that.
The data is then used to make more timely and accurate tropical cyclone weather forecasts.
Storm chasers
Typhoons can pose a threat to lives and property, so the observatory is constantly striving to update its forecasting methods. One way of doing that is to fly data-collection missions with the Government Flying Service right into the heart of tropical cyclones.
The Government Flying Service has been conducting storm reconnaissance flights for the observatory since 2011.
A Jetstream-41 fixed wing aircraft equipped with a meteorological measuring system is flown towards the centre of a cyclone to record raw data including temperature, humidity, air pressure, wind direction and wind speed.
The observatory then combines the information provided by the aircraft with computer weather models and other meteorological data to calculate the storm's track and intensity.
Hong Kong is one of the few meteorological authorities in the Asia-Pacific region with the capability of conducting regular data collection flights.
When tropical storm Linfa approached Hong Kong in July this year, Observatory Scientific Assistant Leung Kwai-kong took his seat on the plane and flew to the centre of the storm. He recalled that the aircraft was shaking so violently he thought he would be thrown out of his seat, despite being strapped in by his seatbelt.
"I've been collecting typhoon data for about five years, but that was the first time I got so close to a typhoon. I felt like I was really doing a service for the Hong Kong people on the frontline," he said.
Government Flying Service Captain Keith Kwong said sending an aircraft so close to a storm is a difficult mission and goes against his training of avoiding bad weather.
"Pilots normally learn how to avoid adverse weather like typhoons so we can provide a safe flight for passengers. But for this task, a comfortable flight is not the priority as we're trying to gather all the weather data for the observatory so they can study the storm and provide better forecasts."
Captain Kwong said Government Flying Service pilots are proud to serve the Hong Kong people in this way.
Seafaring mission
The observatory not only looks to the sky to collect weather data. It also enlists the help of a group of locally-based voluntary observing ships to study climatic conditions in ocean areas.
Ship officers on board make regular weather reports and send them to meteorological centres.
The ships' weather observations provide vital information needed to identify the prevailing weather systems and are especially important for the preparation of sea area forecasts and timely hazardous weather warnings.
In June this year, a drifter buoy equipped with air pressure and sea surface temperature sensors was deployed over the central part of the South China Sea for the first time.
Observatory Senior Experimental Officer Dickson Lau said the buoy, carried along by ocean currents over a data-sparse sea area, was able to take temperature readings and transmit the data to the observatory every hour via satellite.
During one container ship's voyage from Hong Kong to Singapore from June 13 to 18 this year, seven weather balloons carrying radiosondes - small, expendable instrument packages suspended below a balloon - were launched to collect meteorological data such as air temperature, humidity, wind direction and wind speed in the upper atmosphere over the South China Sea.
Mr Lau said both the drifter buoy and weather balloons allowed the observatory to collect indispensable weather forecasting data over the South China Sea and the surrounding areas, which helped contribute to the region's marine safety.
