P4.12
Response of the strating dates and the length of seasons and the Yellow River in mainland China to global warming
Yundi Jiang, National climate center/China Meteorological Administration, Beijing, China
The climatic seasons in China have changed substantially during the past decades. In the majority of the country, the length of summer has extended and that of winter has shortened since the 1950s. These changes in the length of seasons are linked to the changes in the starting dates of seasons. Namely, the starting date of summer has advanced and that of winter has shifted back. Averaged across the whole country, the starting date of summer has been brought forwarded by 5.8 days and the season has extended 9 days. On the other hand, the starting date of winter has been postponed by 5.6 days and the season has shortened 11 days. The changes for spring and fall are relatively smaller. Particularly, spring has started earlier by 5.7 days but shortened by 0.3 day, and fall has started later by 3.2 days but lengthened by 2.3 days. The changes in seasons exhibit apparent regional differences. They are more significant in the north than in the south where the trend of some local changes in seasons is opposite to that of the rest of the country. The authors quantitatively describe the changes in the characteristics of ice phenology including the flow rate and freeze/breakup dates of the Yellow River based on observations of the past 50 years. In both upstream and downstream portions of the Yellow River, increasing temperature delays the freeze date and advances the breakup date, thus decreasing the number of freeze days and the expanse of river freeze. Also, in the lower river, while the location of earliest freeze exhibits little change over the last 50 years, the upstream fringe of ice breakup has shifted downstream significantly.
Poster Session 4, Climate of the 20th Century (C20C) Poster Session
Wednesday, 23 January 2008, 2:30 PM-4:00 PM, Exhibit Hall B
Previous paper Next paper