Annual Temperature and Precipitation Trends in Japan

The Japan Meteorological Agency recently released an analysis of long-term changes in average annual surface temperatures and annual precipitation in Japan from 1898 to 2002.

The long-term trend indicates that of surface temperature have been rising, by approximately one degree Celsius in the past 100 years. Until the 1940s, there was a relatively low-temperature period, but the temperature trend began to a rise thereafter. After a high-temperature period in the 1960s, there was a relatively low-temperature period again until the mid-1980s. In the late 1980s, the surface temperature started to rise dramatically.

Most of the highest annual averages occurred after 1990, a trend that is thought to coincide with the rise in the average global surface temperatures.

Although Japan's surface temperature in 2002 was lower than in 1990 (the warmest since record keeping began) it was still 0.53 degrees above average, the fifth-warmest year since 1898.

The trend of precipitation is showing a moderate decline in the long-term, but the year-to-year variability is growing. The annual precipitation in 2002 was 91 percent of the average, and the third consecutive year below average.

The calculation of surface temperatures was based on data collected from the agency's 17 observation sites where consistent long-term data were available and where changes in the surrounding environment such as urbanization were relatively minor. The calculation of precipitation was based on data from all 51 sites in the country, which provided consistent long-term data.



Posted: 2003/07/17 01:06:13 PM
Japanese version