Set-asides for carbon sequestration: implications for permanence and leakage     

Bin Sun  Brent Sohngen 《Climatic change》2009,96(3):409-419

This paper examines the potential role of forest set-asides in global carbon sequestration policy. While set asides that protect forests from timber harvests and land-use conversion may alleviate concerns with permanence, and they may provide large ancillary environmental benefits, they may also lead to large leakage. This paper uses a global land use and forestry model to examine the efficiency of three crediting schemes for set-asides. The results show that if set-asides are integrated into a global forestry carbon sequestration program that includes a wide range of other management options, then 300 million hectares of land would be set-aside, and up to 128 Pg C could be sequestered in global forests by 2105. Under alternative policies that focus exclusively on set-asides, more forestland can be set-asides, up to 3.2 billion hectare, but these policies invite large leakage in the near-term, and in the long-run, they less net carbon is removed from the atmosphere. Specifically, leakage is estimated to be 47–52%, depending on the policy, and by the end of the century, up to 17% less carbon will be sequestered in all forests.  相似文献   

Parameterization of Sheared Convective Entrainment in the First-Order Jump Model: Evaluation Through Large-Eddy Simulation   总被引：2，自引：0，他引：2  

Jianning Sun  Qiangjun Xu 《Boundary-Layer Meteorology》2009,132(2):279-288

In this note, two different approaches are used to estimate the entrainment-flux to surface-flux ratio for a sheared convective boundary layer (CBL); both are derived under the framework of the first-order jump model (FOM). That suggested by Sun and Wang (SW approach) has the advantage that there is no empirical constant included, though the dynamics are described in an implicit manner. The second, which was proposed by Kim et al. and Pino et al. (KP approach), explicitly characterizes the dynamics of the sheared entrainment, but uncertainties are induced through the empirical constants. Their performances in parameterizing the CBL growth rate are compared and discussed, and a new value of the parameter A ₃ in the KP approach is suggested. Large-eddy simulation (LES) data are employed to test both approaches: simulations are conducted for the CBL growing under varying conditions of surface roughness, free-atmospheric stratification, and wind shear, and data used when the turbulence is in steady state. The predicted entrainment rates in each case are tested against the LES data. The results show that the SW approach describes the evolution of the sheared CBL quite well, and the KP approach also reproduces the growth of the CBL reasonably, so long as the value of A ₃ is modified to 0.6.  相似文献   

2008年11月初大雾过程边界问题分析   总被引：1，自引：1，他引：0  

王玮  黄玉芳  孙建玲 《气象》2009,35(11):117-122

利用常规观测资料和NCEP1°×1°再分析资料对2008年11月初发生在中国东部的一场大雾的边缘区域进行诊断分析,结果表明:在雾区的边缘,能否成雾的因素除湿度、风速和逆温等基本条件外,近地面散度场与垂直风速对雾的形成也有相当重要的作用,其中低层辐合高层辐散区的边缘和雾区的边缘有较好的对应关系,950hPa上方的下沉速度能够阻止水汽的向上扩散,而越往上越大的上升速度意味着雾区的消散.  相似文献   

Study of Station Heavy Rainfall Forecasting Method Based on the MM5 Model Result     

Wu Jun  Sun Chengwu  Pei Hongqin  Yu Yanmin 《山东气象》2008,28(3)

  相似文献   

使用DOS批处理文件备份自动气象站数据     

孙卫卫  宗晓鸿 《山东气象》2008,28(1):54-55

从备份自动站数据文件的实际需要出发,通过实例由浅及深地介绍了用DOS批处理文件多目的地、多方式备份自动站数据的方法,包括本机备份、备份到局域网、备份到网络服务器以及自动备份等。  相似文献   

一次大范围降雹天气的CINRAD/CC若干产品分析     

李永振  李薇  孙海燕  刘岩  崔莲 《气象科学》2008,28(1):105-108

本文对2005年6月10日受东北冷涡影响所发生的吉林省南部大范围降雹雷暴天气,利用CINRAD/CC若干产品进行了分析.分析结果表明:在飑线上,雷暴单体在南部新生、中部成熟、在北部消散,整个生命期长达5 h;在飑线的成熟期中低层至中上层可观测到中气旋(M),并伴随着大范围雷雨大风和降雹天气.  相似文献   

城市建筑动力学效应对对流边界层影响的敏感性试验   总被引：3，自引：1，他引：2  

刘红年  苗世光  蒋维楣  刘罡  孙鉴泞 《气象科学》2008,28(6):599-605

本文将大涡模拟应用于城市对流边界层(CBL)湍流结构和流场特征的研究,在大涡模式中,拖曳系数取与建筑物高度及建筑物高度标准差有关的表达式以考虑次网格建筑物对风速和湍流动能(TKE)的面积平均影响.模拟结果表明,由于城市建筑物对气流的拖曳作用,使建筑物冠层及整个CBL内风速大幅度减小,城市冠层内部风速减小尤为明显,在夹卷层内,风速有一明显的跃变.在边界层中部对流运动已经发展成为较强的热泡,城市建筑物的动力学效应使热泡的水平尺度增大,CBL内平均上升气流速度和下沉气流速度减小,同时使CBL中上升气流所占比例比平坦地面增大.城市建筑物使CBL低层热通量、动量通量、速度方差和位温方差明显增大,但对近地层高度以上的湍流量影响不大.  相似文献   

1880-2006年中国夏季雨带类型的年代际变化特征   总被引：1，自引：0，他引：1  

赵振国  朱艳峰  柳艳香  许力  孙林海  李想 《气候变化研究进展》2008,4(2):95-100

 利用1880-2006年中国东部地区夏季降水量及1951-2006年中国160个站夏季降水量和北半球大气环流资料,在夏季降水分型的基础上,研究了夏季雨型的年代际变化规律,分析了夏季各类雨型所对应的北半球500 hPa环流场的主要特征。结果表明：东部季风区和西部区存在着20～40 a左右的年代际振荡趋势,东北区则表现为明显的15 a左右的年代际变化特点;东部季风区四类雨型东亚大气环流差异显著,西部区二类雨型和东北区二类雨型欧亚大气环流的配置基本都相反。  相似文献   

中国区域气溶胶对东亚夏季风的可能影响(Ⅱ)：黑碳气溶胶及其与硫酸盐气溶胶的综合影响   总被引：8，自引：0，他引：8  

孙家仁  刘煜 《气候变化研究进展》2008,4(3):161-166

 利用NCAR的新一代GCM CAM3.0模式耦合一个气溶胶同化系统,研究了中国区域黑碳气溶胶的直接气候效应。结果显示,中国区域黑碳气溶胶引起全球平均辐射强迫为0.13 W/m2,导致除了青藏高原和广西以外的中国大部分地区降温,其中东北、四川和内蒙古中北部降温最显著。由此造成海陆温差缩小,气压差降低,从而总体上使东亚夏季风减弱。但与硫酸盐气溶胶的影响相比,黑碳气溶胶使季风减弱的程度较小,长江中下游地区的降水有所增加。黑碳气溶胶加强了中国东南部地区的对流活动,这与硫酸盐气溶胶的作用相反。同时,探讨了中国区域硫酸盐和黑碳气溶胶的综合直接气候效应。结果表明,硫酸盐和黑碳气溶胶的综合作用与仅有硫酸盐气溶胶的情形十分相似,降水变化的区域也和硫酸盐的保持一致。  相似文献   

1959-2003年中国天山积雪的变化     

杨青  崔彩霞  孙除荣  Ren Yiyong 《气候变化研究进展》2008,4(Z1)

Mcteorological data at 17 weather stations in the Tianshan Mountains from 1959 to 2003 were analyzed to explore the variations in temperature and snow cover.The abrupt change test for snow depth was performed using Mann-Kendall statistic.The spatial distribution of maximum snow depth was calculated by employing GIDS interpolation and DEM data.The results show that mean temperature in winter had a rising trend at a rate of 0.44℃/10a.The minimum temperature in winter increased more evidently at a rate of 0.79℃/10a.The maximum snow depth has obviously deepened at a rate of 1.15 cm/10 a in the past 45 years,and it was about 16% higher than the average during 1991-2003.The Mann-Kendall statistic test of snow depth indicates that the abrupt change occurred in 1976.The maximum increment for snow cover depth occurred in Zhaoshu(Kunes)(39.3%)and Nilka(39.7%)in the west Tiansban Mountains.In contrast,the snow cover depth reduced by 17% in Barkol in the east Tianshan Mountains.There was a primary change periodicity of about 2.8 years in snow cover.In addition,snow cover days with a depth more than 10 cm increased distinctly,however,there was no obvious advance or delay in snow beginning and ending dates.  相似文献