Twice every day, weather balloons launched from the Environment Canada compound in Whitehorse float up into the skies and collect data on the upper atmosphere. This information is essential for predicting the weather in the Yukon, but it also helps weather forecasters in other parts of the world.

Weather does not stop at national boundaries, and neither does the need for information about the weather. Fortunately for all of us, weather data from around the world is shared through a global system that shows just how well different countries can cooperate when they really want to do so.

Sharing this information requires a combination of advanced technology, routine dependability and an international language that weather forecasters everywhere can interpret.

The World Meteorological Organization (WMO) coordinates a near-instantaneous exchange of weather information around the globe. A specialized agency of the United Nations, the WMO began operating in 1951 and now has 183 members around the world.

The WMO's system of nine satellites collects weather data supplied by more than 10,000 land-based stations, and another 7,000 stations based on ships. As well several hundred buoys equipped with automatic weather stations also supply weather data.

Observers on the ground record information on the surface weather while balloons collect information on the upper atmosphere. With both systems, the information is translated into a numerical code.

Brian Forsyth, the program lead for the Whitehorse Upper Air program with Environment Canada, calls this free exchange of information among countries truly unique."It is the only thing I can think of where people share information back and forth in this way. There are no borders."

Whitehorse is one of about 1,000 stations in the world that collects information on the upper atmosphere with weather balloons. Launched everyday at 4:15 a.m. and again at 4:15 p.m., the balloons drift into the upper atmosphere to an elevation of 35,000 metres.

On-board instruments collect data on wind direction and speed, temperature, relative humidity and pressure at different levels of the atmosphere, and relay this information back to Whitehorse every few seconds.

But the data does not sit in one place for long. After it is translated into a numerical code, it is relayed first to Montreal, then on to Suitland, Maryland, the central collection area for North America. From there it is distributed to rest of the world via four other collection hubs.

The WMO estimates that every day, its high-speed links transmit more than 15 million data characters and 2,000 weather charts around the world.

The data for North America is used to generate a set of forecast charts that provides information on four different levels in the atmosphere. These forecast charts -- put out twice a day -- give a five-day look into the future.

Forsyth explains that forecasters on other continents also need this same information since weather does not stay put. "Weather is not local. It comes from some place and goes some place. People in England need to know what is happening over North America," he says.

Since the Yukon weather office closed down, the territory's forecasts have been generated at a regional center in Kelowna. Forsysth says that theoretically someone in China could generate a Yukon forecast, using information from the charts, but they would not have the local knowledge needed to fine tune a forecast.

Two of the forecasters previously working in the Yukon transferred to the Kelowna office. As well, all of the meteorologists working on Yukon forecasts spent some time in the territory learning about local conditions.

While the data on the upper atmosphere is important for the continental charts put out by the WMO, forecasters also need information on the surface weather. At flight service stations and community airports around the territory, observers go out every hour and take notes on factors such as cloud conditions, visibility, temperature, wind, pressure, and precipitation.

Canada has a total of 32 stations using weather balloons, but Whitehorse is the only one where the balloons are launched automatically. The device, called an Autosonde, is being tested here to see how well it performs in cold temperatures.

The upper air program is not inexpensive. Each weather balloon carries a device called a Radiosonde that collects the data. These small boxes cost just over $100 each and cannot be retrieved from the balloons. The balloons cost another $25 or so each.

Forsyth says that he continues to be impressed by this elaborate global system, and the wealth of information that it provides. "It is just amazing how it all works," he says.