青藏高原东北部农牧交错区气候变化及其对草场植被的影响   总被引：3，自引：1，他引：3       下载免费PDF全文

王建兵  李晓媛  王振国 《干旱地区农业研究》2007,25(6):216-219

利用青藏高原东北部12个地面气象站1961-2000年的降水、气温资料，分析了区域内近40a来气候的交化及其对牧草的影响。结果表明，青藏高原东北部农牧交错区从20世纪80年代末开始有明显的暖干化趋势，受气候暖干化，以及超载过牧、草地鼠虫害、滥挖乱垦等因素共同影响，区域内牧草产量下降，牧草群体结构平均密度明显减少，导致草场植被稀琉，草场退化现象B趋严重。  相似文献   

内蒙古近45a蒸发量气候变化特征分析   总被引：2，自引：0，他引：2  

张存厚  吴学宏  李永利 《干旱区资源与环境》2007,21(12):93-98

利用内蒙古境内35个气象站1960~2004年逐日蒸发皿蒸发量资料,研究了大兴安岭森林区、草甸草原区、典型草原区、荒漠化草原区、草原化荒漠区和典型荒漠区6种不同生态类型区域蒸发量的气候变化,揭示了不同生态类型区蒸发量的特征值及蒸发量年内、年际变化规律,推断得出内蒙古不同生态类型区域今后蒸发量的气候变化趋势。  相似文献   

乌兰布和荒漠人工绿洲小气候效应研究   总被引：7，自引：0，他引：7  

王君厚  周士威 《干旱区研究》1998,15(1):27-34

通过对乌兰布和荒漠东北边缘人工绿洲内和荒漠对照区各小气候因子连续１２年的同步观察,采用模糊综合评判方法,全面定量分析了防护森体系不同时期的小气候效应及变化规律,评价结果表明,绿洲防护要体系对各气象因子有前显的影响,特别是降低风速,抑制蒸发,提高空气湿度等方面尤为突出,综合小气候效应明显,１２年间效益值增加了０．７４６,增长率为３１％,绿洲防护林体系对小气候的改善作用各时期不同,从综合效益值来看,初  相似文献   

岱海游乐场孔孢粉分析及其2500年来古气候演化   总被引：1，自引：0，他引：1  

乌云格日  刘清泗 《干旱区资源与环境》1998,12(3):21-27

本文通过对岱海游乐场钻孔剖面沉积物孢粉的定性、半定量分析,并结合岩性、岩相变化,初步恢复了该地区２５００年来古植被、古气候演化过程。研究结果表明,岱海湖盆自２５００年来植被类型有典型草原—灌丛草原—森林草原—灌丛草原的演化过程,古气候有较暖湿—较暖干—较冷干—较冷湿—较冷干的变化过程。  相似文献   

我国气候因素的变化对奶牛生产的影响   总被引：3，自引：0，他引：3  

安立龙  刘松龄 《家畜生态》1998,19(4):36-40

在分析我国气候因素变化的基础上,着重阐述了气候因子对我国奶牛采食,饲料利用率,产奶量和乳成分,奶牛的繁殖力,日增重及发病率等生产性能的影响。结果表明,高温高湿是奶牛生产的主要环境因子。作者不提出了控制奶牛环境的若干措施。  相似文献   

The fallacy of the missing middle: physics →…→ fisheries     

MICHAEL BAUMANN 《Fisheries Oceanography》1998,7(1):63-65

In this paper I discuss some of the shortcomings of today's marine science in response to a recently published paper by Ann Gargett (1997). Three problem areas have been identified in the field linking climate forcing and fish production: First, the yet-to-be established observational proof for a relationship between the two; Second, the strongly neglected biology of organisms at evolutionary and ecological time scales; and thrird, the disregard for spatial and temporal scales in the discussion of mechanisms and supporting data.  相似文献   

三明各县（市）汛期特涝年气候特征分析     

章达华  ;沈永生  ;伍毓柏  ;邱章奴  ;刘玉  ;王珊珊  ;王正廷  ;黄发明  ;陈艳蝶 《甘蔗(福建)》2009,(1):44-49

对福建省三明各县（市）1961—2008年汛期（5、6月份）的降水资料进行统计分析，揭示汛期雨量特多、特涝和异常偏涝年份的时间、地域分布特征和周期演变规律；用500hPa月平均高度场资料分析了2005年汛期异常偏涝的环流特征，并就2005年汛期异常偏涝与历史上特涝年的环流形势进行了对比分析。结果表明：5、6月份由于东亚大槽明显偏东，副高面积大、强度强，脊线明显偏南，印缅槽强度偏强，导致西风槽非常活跃，不断东移、南压，这是造成2005年三明各县（市）汛期异常偏涝的主要原因；5、6月份由于逐日副高脊线位置适中、稳定，导致三明各县（市）汛期开始早、结束迟、持续时间长，这是造成2005年汛期异常偏涝的原因之一。  相似文献   

发展过渡带地区草坪业若干问题探讨   总被引：5，自引：3，他引：2  

周嘉友  汤承 《草业科学》1998,(3)

介绍我国过渡带地区地理位置和主要植被气候特点，分析了过渡带地区草坪业存在的主要问题和促进该地区草坪业发展的主要措施。  相似文献   

A synthesis of large-scale patterns in the planktonic prey of larval and juvenile cod (Gadus morhua)     

M. R. HEATH  R. G. LOUGH 《Fisheries Oceanography》2007,16(2):169-185

Data from 40 published studies of the diet composition of larval and juvenile cod (Gadus morhua) from around the northern North Atlantic were summarized to assess generic patterns in ontogenetic and regional variability in the key prey. The results showed that larvae at the northern edge of the latitudinal range of cod depend primarily on development stages of the copepod Calanus finmarchicus, whilst those at the southern edge depend on Para‐ and Pseudocalanus species. Juvenile cod preyed on a wider range of taxa than larvae, but euphausiids were the main target prey. Analysis of regional variations in the relative abundances of C. finmarchicus and Para/Pseudocalanus spp. in the plankton, as estimated by the continuous plankton recorder (CPR) surveys, showed a similar geographical pattern to the larval cod stomach contents. Comparison of CPR data from the 1960s and 70s with data from the 1990s showed that the boundary between C. finmarchicus and Para/Pseudocalanus spp. dominance has shifted northwards on both sides of the Atlantic, whilst the abundance of euphausiids in the southern cod stock regions has declined. The results are discussed in relation to regional differences in the response of cod stocks to climate variability.  相似文献   

Performance of Agricultural Systems under Contrasting Growing Season Conditions in South-western Quebec     

J. J. Almaraz  F. Mabood  X. Zhou  I. Strachan  B. Ma  & D. L. Smith 《Journal of Agronomy and Crop Science》2009,195(5):319-327

Climate change will alter temperature and rainfall patterns over North American agricultural regions and there will be a need to adapt crop production systems to the altered conditions. A set of field experiments were conducted in south-western Quebec, Canada, with soybean ( Glycine max L.), corn ( Zea mays L.), sorghum ( Sorghum bicolor L.) × sudangrass ( Sorghum sudanense Piper) hybrid and switchgrass ( Panicum virgatum L.) under two tillage and three nitrogen fertility regimes, to study their performance in three successive growing seasons (2001–2003), two of them with unusually warm and dry conditions. The annual crops were established in two tillage systems: conventional and no-till (NT). All crops except soybean were fertilized with three levels of nitrogen: corn – 0, 90 and 180 kg N ha⁻¹, sorghum-sudangrass – 0, 75 and 150 kg N ha⁻¹, switchgrass – 0, 30 and 60 kg N ha⁻¹. The 2001 and 2002 seasons were hotter and drier than the 2003 season, which was the most favourable for crop growth. The capacity of the crops to yield in dry seasons was as follow: switchgrass > sorghum-sudangrass > corn > soybean. The corn and sorghum-sudangrass responses to nitrogen fertilizer were low in 2001 due to the combined effect of dry growing season and coarse soil texture. Soybean did not perform well under NT. Corn yielded better at the highest nitrogen fertilizer rate under NT when the early season was warmer than the normal. Our results show that switchgrass and sorghum-sudangrass could be an option in south-western Quebec if the frequency of hot and dry seasons increase in the future, because of climate change.  相似文献