Regional Environmental Differentiation in China Sincethe Mid-Pleistocene Inferred from Lake Recordsand Its Relation with East Asian Monsoons

Comparative study of long lake records in different regions in China can provide some significant information about the regional differentiation of the environment and Asian monsoon activities. However, intensively studied lacustrine cores with a span of a few hundred thousand years are very rare in China. The available examples are only three long cores from the Zoige basin in the eastern Qinghai-Tibet plateau, the Qaidam basin in the northern Qinghai-Tibet plateau and the Dianchi basin in the Yunnan plateau respectively. The results show that the regional environmental differentiation since the Mid-Pleistocene involved three stages, i.e. 780-480, 480-160, 160-0 ka B.P. In each of the three stages different regions of China had their own distinctive environmental characteristics, indicating that the uplift of the Qinghai-Tibet plateau played a major role in the environmental differentiation process.     

Winter mortality risk for American ginseng (Panax quinquefolium) in Saskatchewan

North American ginseng is native to the deciduous forest region of eastern North America but is now cultivated in areas well beyond its natural range. In recent years an expanding market has attracted growers in climatically less suitable regions, including the Canadian prairies. The ginseng root requires at least four years to reach marketable size and is sensitive to injury when the temperature drops below about −4°C. Such temperatures are not unusual in the prairies; thus winter kill is a hazard that may limit ginseng production in this region of Canada. This study analyses the risks of winter soil temperatures falling below levels critical for the survival of ginseng in Saskatchewan. It appears that winter conditions may be too severe for reliable production of this lucrative crop, although application of straw mulch and additional benefits of trapped snow could reduce the risk of winter kill.     

西南季风对中国自然环境影响的区域变化研究

西南季风作为亚洲季风重要组成部分，对中国自然环境也有较大影响。西南季风建立以后，因青藏高原高度不足以阻止西南季风这一深厚的大气环流系统，加之西南季风厚度随着山地尤其是横断山脉的上升而不断增厚、增强。南支西风急流的气旋性质对西南季风深入有引导作用，西南季风较东南季风活动性强，影响区域范围大，影响到太行山以西中国大部分地区。中更新世时，青藏高原隆升至海拔平均约3000m的高度，同时期也出现了第四纪最大冰期与最大温暖期，高原热力和动力作用得到了进一步加强，西南季风厚度加大，西南季风对中国自然地理环境深化起到重要作用。晚更新世以来青藏高原隆升至现今的平均约4500-5000m的高度，特别是喜马拉雅山脉的隆起，足以阻挡大部分西南季风进入西藏高原和中国内陆地区，西南季风影响范围退缩到长江上游以南的西南地区局部和青藏高原东部地区。     

东亚地区夏季风活动与对流层顶臭氧含量变化的关系探讨

利用1976～2001年东亚地区的风场、气压场和对流层顶臭氧浓度观测资料,选取并计算了3种当前使用较为广泛的东亚季风指数,分析了夏季期间上述指数与对流层顶臭氧的相关,从而对东亚地区季风活动与对流层顶臭氧含量分布的关系进行了探讨.分析表明:(1)东亚SMI夏季风指数的强弱与西太平洋副热带高压区的对流层顶臭氧之间存在着正相关,且相关性较好;(2)指数EAMI与对流层顶臭氧存在相关,具体表现为在南海热带季风区存在着负相关、在大陆--日本副热带季风区存在正相关、西太平洋副热带高压区存在较好的正相关;(3)而在副热带梅雨锋区,EASMI指数的强弱与对流层顶臭氧含量变化存在较好的正相关,在热带季风槽区,EASMI指数的强弱与对流层顶臭氧含量变化存在较好的负相关.     

冬小麦光合生产潜力数值模拟*

利用中国小麦生态实验资料建立了黄淮海地区冬小麦发育阶段模式和光合作用、呼吸作用等模式,由这些子模式连结成为一个可以模拟瞬时光合作用的,充分考虑了叶片空间分布特征的冬小麦光合生产潜力模式。运用该模式研究结果证明冬小麦光合生产潜力与抽穗前10天至成熟期辐射量相关性最大。黄淮海地区冬小麦光合生产潜力可达到800kg/亩～1000kg/亩,与牛文元计算结果相近。功率谱分析结果表明北京地区光合生产潜力存在3年～4年和9年～10年的变化周期。此外,文中还给出了CO₂升高后冬小麦光合生产潜力的可能变化情况。     

THE EARLY SUMMER FLOOD PERIODS OF SOUTHERN CHINA AND THE SUMMER MONSOON CIRCULATION OF EAST ASIA

Based on the thermodynamic characteristics of the summer monsoon and foe change of the lower layer wind fields, the relation between the early summer flood periods of southern China, Including the first flood period of South China and the plum rains period of the middle-lower reaches of the Yangtze River and the activities of the summer monsoon is analysed.The establishment processes of the summer monsoon circulation of East Asia are investigated.It is shown that the beginning and ending of the flood periods are exactly in accordance with the arrival and departure of the fore boundary of the summer monsoon.The establishment process of the circulation from the very beginning of the arrival of the monsoon to the time of great prosperity of development are not the same for each year.They can be classified into four categories.Each category may have four or three stages.Besides, the structure of the summer monsoon regime of East Asia is not unitary.There exist four types of structure model of the monsoon regime of East Asia.     

A FURTHER STUDY ON INTERACTION BETWEEN ANOMALOUS WINTER MONSOON IN EAST ASIA AND EL NINO*

The interaction between anomalous winter monsoon in East Asia and El Nino is further studied in this paper.The new results still more proved a previous conclusion:there are clear interactions between El Nino and winter monsoon in East Asia.The continual westerly burst andstronger cumulus convection over the equatorial central-western Pacific caused by stronger wintermonsoon in East Asia can respectively excite anomalous oceanic Kelvin wave and stronger atmospheric intraseasonal oscillation in the tropics,then excite the El Nino event through air-sea interction.In El Nino winter,there are warmer and weaker winter monsoons in East Asia.The El Nino will still reduce the intensity of intraseasonal oscillation and leads it to be barotropic structure.     

东亚冬季风强度异常与夏季500hPa环流及我国气候异常的关系

利用一个耦合海气模式，用数值试验方法分析了１９８２／１９８３ＥＮＳＯ期间的暖池和赤道事带的相互使用对大气表面流场和散度的影响。结果指出，ＥＮＳＯ高峰期和成熟期ＳＰＣＺ比ＩＴＣＺ更重要；ＥＮＳＯ的形成初期和衰减期ＳＰＣＺ和ＩＴＣＺ同样重要。     

亚洲夏季风环流的低频振荡与江淮梅雨

根据欧洲中心1980～1983年4～9月的200hpa和850hpa格点资料，利用滤波技术和经验正交函数（EOF）分析方法，研究了亚洲地区夏季风环流低频振荡的特征及其对江淮地区梅雨的影响。结果表明：季风环流的低频变化存在三种主要的空间分布型，其中，第一特征向量与江淮地区梅雨期的大尺度环流形势相似，它们的位相转换与季风系统各主要成员的活动密切相关；江淮地区低频气旋性切变线的活动对梅雨期的长短乃至该区的干旱和洪涝有重要的影响。     

Planning MONTBLEX — An overview

The multi-institutional experiment MONTBLEX aimed at sensing and studying the atmospheric boundary layer over the monsoon trough region of the northern plains of India during the summer monsoon of 1990. Four core facilities consisting of micro-meteorological towers and state-of-the-art instrumentation were created along the trough axis. This overview emphasizes the key features of project planning, management and execution, and provides detail? of all the experimental observation sites.