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鲁西南木本植物生长季及物候期持续日数对气候变暖的响应 总被引：2，自引：0，他引：2
以1981-2010年中国鲁西南地区的植物为研究对象,采用统计分析法研究7种木本植物生长季与物候期持续日数对气候变暖的响应规律。结果表明：1981-2010年中国鲁西南地区气温呈极显著上升趋势（p<0.01）,随着气候变暖,木本植物春季物候期间隔缩短,秋季物候期间隔延长,全生长季延长,且全生长季变化趋势比各物候持续期变化趋势明显;展叶持续期主要与上月、当月和持续月平均气温呈负相关,其中梧桐展叶持续期与当月平均气温呈极显著负相关（p<0.01）;旱柳和刺槐开花持续期与持续月平均气温呈显著正相关（p<0.05）;叶变色持续期和落叶持续期与上月、当月、结束月和持续月平均气温呈正相关,其中旱柳与平均气温达到显著正相关（p<0.05）。木本植物全生长季与气温呈正相关,其中旱柳生长季变化对气候变暖的响应最敏感,其次是榆树、梧桐和楝树生长季变化对气候变暖的响应较敏感;随着年平均气温每升高1 ℃,植物生长季延长3.0-20.0 d;年平均最高气温每升高1℃,生长季延长5.0-14.0 d;年平均最低气温每升高1 ℃,生长季延长2.0-18.0 d。 相似文献
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Trends in precipitation extremes over the Yellow River basin in North China: Changing properties and causes 总被引：1，自引：0，他引：1 
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下载免费PDF全文 The Mann–Kendall test, composite analysis, and 68 high‐quality meteorological stations were used to explore the spatiotemporal variations and causes of precipitation extremes over the Yellow River basin (YRB) during the period of 1960–2011. Results showed that (a) the YRB is characterized by decreases of most precipitation indices, excluding the simple daily intensity index, which has increasing trends in most locations, suggesting that the intensity of rainfall and the probability of occurrence of droughts have increased during the last decades. (b) Trends of extreme precipitation show mixed patterns in the lower reach of the YRB, where drought–flood disasters have increased. The increases in heavy rainfall and decreases in consecutive wet days in recent years over the northwestern portions of the YRB indicate that the intensity and frequency of above‐normal precipitation have been trending upward in domains. In the central‐south YRB, the maximum 1‐day precipitation (RX1day) and precipitation on extremely wet days (R99p) have significantly increased, whereas the number of consecutive dry days has declined; these trends suggest that the intensity of precipitation extremes has increased in those regions, although the frequency of extreme and total rainfall has decreased. (c) The spatial distributions of seasonal trends in RX1day and maximum 5‐day precipitation (RX5day) exhibited less spatial coherence, and winter is becoming the wettest season regionwide, particularly over the central‐south YRB. (d) There were multiple and overlapping cycles of variability for most precipitation indices, indicating variations of time and frequency. (e) Elevation is intimately correlated with precipitation indices, and a weakening East Asian summer monsoon during 1986–2011 compared to that in 1960–1985 may have played an important role in the declines in most indices over the YRB. Therefore, the combined effects from local and teleconnection forcing factors have collectively influenced the variations in precipitation extremes across the YRB. This study may provide valuable evidence for the effective management of water resources and the conduct of agricultural activities at the basin scale. 相似文献
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