Spatiotemporal changes in the bud-burst date of herbaceous plants in Inner Mongolia grassland

Journal of Geographical Sciences - Phenological modeling is not only important for the projection of future changes of certain phenophases but also crucial for systematically studying the...     

Relationships between climate change,agricultural development and social stability in the Hexi Corridor over the last 2000 years

This case study of the Hexi Corridor, Northwestern China, utilizes statistical methods to estimate quantitatively the interaction at a regional level between climate change, ancient social developments, and political coping strategies over the past 2000 years. The data is sourced from high-resolution reconstructions of climate series(temperature and precipitation), and historical records of cultivated land, war, population, and changes in regional administrative systems. The results show that moisture conditions played a more significant role than temperature in driving land reclamation in the Hexi Corridor. Analysis also showed a negative correlation between war frequency and the area of cultivated land in the Corridor over 20-year time intervals. Population growth was found to have a significant positive correlation with the cultivated land area during the study period. The results indicate that a climate-induced decline in agricultural production and the subsequent fluctuations in population could act as a trigger for social unrest, which is especially true at the mutual decadal time-scales. However, the interaction with administrative reform also suggests that, in the face of social and economic turmoil, a reasonable administrative hierarchy could strengthen the social governance of regional government, and promote social stability and economic development at a regional level. The study substantiates this notion with empirical quantitative evidence.     

物候学方法在历史气候变化重建中的应用

利用历史物候记录重建的气候变化结果,显著地增进了人类对过去气候变化特征的认识。但现有研究在历史物候记录的提取与处理、重建方法的选择、重建结果的精度评估等方面需要进一步总结梳理。通过归纳历史物候记录的资料源以及在历史物候记录预处理过程中需要解决的物种鉴别和物候期确定问题,对现有重建方法进行总结,发现较早的研究采用了古今对比法,而近年来的研究多采用更为复杂的回归和过程模型法。上述物候学方法的重建结果对认识中世纪暖期、小冰期和近百年等典型时段的历史气候变化特征提供了重要依据,同时物候学方法重建结果与其他代用资料重建结果往往表现出较高的一致性。未来研究可在历史物候记录的整编与利用、重建方法的准确性评估与改进以及不同重建结果比对等方面,进一步深入开展工作。     

物候模型在北京观赏植物开花期预测中的适用性

以北京地区玉渊潭公园杭州早樱 (1998—2012年)、密云农业气象试验站白玉兰 (1996—2012年) 及颐和园公园山桃 (1981—2012年) 物候观测资料和海淀、密云气象站的1981—2012年逐日平均气温观测资料为基础,分别应用国际通用的3种物候模型 (SW模型、UniChill模型和统计模型) 对以上植物的始花期和盛花期建模,并评估模型适用性。结果表明:SW模型在北京地区3种观赏植物开花期预测中适用性最高,其交叉检验的均方根误差仅为1.93~3.58 d, 其次为UniChill模型 (均方根误差为2.49~3.79 d),统计模型效果最差 (均方根误差为2.36~4.24 d)。因此,推荐在观赏植物开花期预测业务中采用SW模型。