Friday, 16th September 2011

Weather and Sports

http://www.weather.gov.hk/blog/en/archives/00000109.htm

In the summer time, many people enjoy outdoor sports such as swimming, windsurfing and paragliding. To engage in these sports, apart from one's own skills, physical strength and courage, favourable weather condition is also indispensible. While inclement weather like rainstorms, lightning and tropical cyclones will hinder the conduct of outdoor sports, some other seemingly unremarkable changes in the weather, such as temperature, humidity, wind direction and speed, rainfall, etc. can affect one's performance in the sports.
For example, windsurfing is powered by wind on a sail. In a day with weak winds, sailing will be difficult. On the other hand, sailing will be dangerous if the winds are getting too strong, as not every windsurfer can maintain control under strong winds. One may notice that the French Open or Wimbledon will usually suspend when it rains, not only because the tennis ball gets heavy after absorbing rain water, but also because the hard courts or grass courts may become slippery and the bricks and soil of the clay courts may stick together in rain, leading to falls or sprains easily. Paraglider pilots need to calculate the takeoff and landing locations, and to adjust the route and flight speed according to the prevailing upper-air conditions such as wind direction, wind speed, and visibility[1]. Athletes playing track and field events such as sprint and hurdles can achieve significant differences in performance under tail wind and head wind conditions. For this reason, a maximum tail wind of 2 metres per second is allowed for a 100 m performance to be considered eligible for Olympic records[2].
Weather condition is often a decisive factor to victory for the professional athletes, so being able to grasp accurate weather information in real time is particularly important to them. Although the work of the Hong Kong Observatory, as a meteorological agency, is not directly related to sports, it has made contributions by offering meteorological support to a number of past major international sports competitions.
In the 2004 Athens Olympic Games, at the invitation of the Hong Kong Windsurfing Team, the Observatory provided information on Athens' weather and tailor-made weather forecast to the team. Although separated by half of the earth and with little prior knowledge of the local weather in Athens, the Observatory, through the use of technology by setting up a high resolution computer model and the mastery of various weather scenarios in Athens by our professional forecasters, was pleased to finally overcome the major challenge. Besides, the Observatory has also set up a dedicated website to facilitate the access of real-time weather information at the competition venue by the team, and to help them develop the best race strategies. Although Lee Lai-shan, the core member of the windsurfing team, finished the competition in fourth place, the Observatory was highly praised by the team and both parties gathered to celebrate for the first successful cooperation after the competition.


Figure 1 The Hong Kong Windsurfing Team autographed on the historic weather forecast for Athens.


Figure 2 The Hong Kong Windsurfing Team and Observatory's colleagues celebrated
the first collaboration after the 2004 Athens Olympic Games.


During the 2008 Beijing Olympic Games, the Observatory again provided weather information at the competition venue to the Hong Kong Windsurfing Team. On top of that, at the invitation of the World Meteorological Organization, the Observatory also migrated its in-house developed nowcasting system named SWIRLS ("Short-range Warning of Intense Rainstorms in Localized Systems") to Beijing, so as to assist the local authorities in providing severe weather forecasts for the individual Olympic venues.
For the Olympics equestrian events held in Hong Kong in the same year, the Observatory specially built a heat stress monitoring system, which supplied the most critical piece of weather information to the events. The system measures the degree of stress experienced by animals or human beings due to high temperatures. Horses are indeed very sensitive to weather changes. It is both hot and humid during the summer time in Hong Kong, and horses will feel uncomfortable under such weather. According to the guidelines of Fédération Equestre Internationale[3], if the heat stress index rises to 30 to 32 degrees, additional measures are needed to prevent the body temperature of the horses from getting too high. When the index reaches 33 degrees or above, the very hot weather may even endanger the health of the horses, and veterinary advice should be required before continuing with the game. The heat stress index measured by the Observatory served as a helpful objective guidance to the organizer for conducting the events[4].
The Observatory also contributed to the meteorological support for the 2009 Hong Kong East Asian Games, 2010 Guangzhou Asian Games and 2010 Commonwealth Games in New Delhi by deploying its computer model, nowcasting system and the heat stress index measurement technique. In the just-completed 2011 Shenzhen Summer Universiade, apart from providing real-time weather observations and forecast data to the Shenzhen Meteorological Bureau, the Observatory for the first time ever participated in the joint weather conference via video link with experts from the China Meteorological Administration to discuss the weather condition during the Universiade.


Figure 3 The Hong Kong Observatory participated in a joint weather conference with the China
Meteorological Administration on 12 August 2011 to discuss the weather that might
affect the opening ceremony of the Universiade.


In fact, not only professional athletes need to be aware of the weather conditions, we all have to do so when engaging in sports in our leisure time. In addition to providing tailor-made meteorological services for the professional athletes, the Observatory has also set up one-stop web pages to make available relevant weather information for aviation sports enthusiasts, water sports enthusiasts, hikers and climbers in Hong Kong. Looking ahead to the 2012 London Olympic Games, the Observatory will, as in the past, continue to provide practical and effective meteorological services for the sports community.
FY Lee and HY Yeung
References :
[1] http://en.wikipedia.org/wiki/Paragliding
[2] http://en.wikipedia.org/wiki/100_metres
[3] Fédération Equestre Internationale Eventing Rules, Annex V: Guidelines of measures to be taken in adverse climatic conditions of heat and humidity. (https://admin.fei.org/Disciplines/Eventing/Rules/Documents/LATEST MEMORANDUM ANNEXES.pdf)
[4] http://www.hko.gov.hk/publica/reprint/r743.pdf (in Chinese only)