August - September, 2006

WEATHER STATIONS IN ACTION :

Vantage Pro2’s Help Study Urban Heat Islands in Tokyo

Global warming and environmental change is everybody’s concern, but Japan, with its small land mass and dense population has been on the leading edge of research on ways to mitigate the negative effects of these changes.

One specific area of concern is urban heat islands, which affect large cities worldwide, and are especially important in Japan, with its dense population and increasing industrialization. The Japanese government is taking phenomenon of urban heat islands seriously, and has set out to gather and analyze data in order to incorporate solutions into their urban planning, engineering, and life style recommendations. And when they needed serious equipment to help in the study, they turned to AOR, Ltd and Davis Vantage Pro2 weather stations.

Urban heat islands describe the observation that cities create their own heat, warming more than their surrounding rural areas. The cause is multifold but boils down more people, buildings, machinery and vehicles, and a loss of natural surface and greenery. This leads to a change in the balance of radiation, heat, and water – and a net change, for the warmer, in temperature.

Our Japanese distributor, AOR, Ltd., was called upon to provide weather stations to study one particular aspect of urban climate in Tokyo: wind paths. Wind paths are locally circulating winds that bring cool air inland from the sea in the day time or down mountain slopes and valleys at night. Large oceanfront cities like Tokyo, Nagoya, and Osaka could benefit from these cooling wind paths – but only if their urban design allows buildings to channel the cool air, not to block it.

Until now, there have been no statistical techniques available to forecast this flow and predict its affects. In July 2005, Professor Toshio Ojima of Waseda University led a project to measure wind direction, speed, temperature; as well as relative humidity at some 200 sites in four areas in Tokyo. The scientists used Vantage Pro2 weather stations to collect this data over a two week period. Balloons with sensors were also used to measure the effect of altitude. The data is now being analyzed to determine how the high-rise buildings, streets, parks, and rivers influence wind paths. Using the results, urban planners will be able to create city plans that mitigate the phenomenon of urban heat islands.

We know the rest of the world will be looking carefully at the results and using them to change the future of the world’s cities. We’re proud that Vantage Pro2 is starring in this important work.

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