气候工程的经济评估和治理核心问题探讨

气候工程技术可以被视作可替代传统减排措施的备选项,主要包括太阳辐射管理和CO2移除两大类技术。两类气候工程技术与传统减排方法的空间、时间、成本、不确定性和风险等方面都具有一些差异性。气候工程技术手段改变了传统的国际气候制度构建基础,产生了一些新的治理问题。对该问题的科学研究,有重要的科学、政策和国际气候外交意义。     

Mapping gamma radiation and its uncertainty from weathering products in a Tasmanian landscape with a proximal sensor and random forest kriging

The radionuclides of potassium (⁴⁰ K), uranium (²³⁸U) and thorium (²³²Th) emit from the land surface gamma radiation that is characteristic of the underlying rocks and the distribution of their weathering products in the landscape. We measured the radiation along widely separated transects using a mobile proximal sensor over a 10 000‐ha region of Tasmania. We supplemented the transect data with information from soil and geological maps and dense data from LandSat and SPOT imagery, a digital elevation model and terrain attributes on a grid at 30‐m intervals so as to map the radionuclides. We used a sequence of steps, starting with a spatial bootstrap and random forests to predict emissions across the study area and at sampling points excluded from the bootstrap samples. The predictions at the sampling points were compared with the observed values to obtain residuals, which were then used to krige them at all points on the 30 m grid. We combined the random forest and kriging predictions on the 30‐m grid to obtain our random forest kriging predictions. Repeating the procedure 100 times provided confidence limits on our results and predictions. The resulting maps of the radionuclides accord well with what we know of the soil, lithology and topography of the region from other sources. Alluvial deposits with large amounts of potassium extend from the foot slopes of the Great Western Tiers and along the flood plains of the Meander River, providing evidence of previous widespread weathering and deposition of the material. The fertile Red Ferrosols (roughly equivalent to Ferralic Nitisols in the World reference base (WRB) classification) on the extensive Tertiary basalt plateau emit little gamma radiation as a result of deep weathering and of potassium movement and accumulation down its talus slopes. The maps show the complexity of the region in terms of soil, lithology and terrain, and they show the merits of gamma radiometry for mapping and understanding the distribution of materials in such regions. Copyright © 2013 John Wiley & Sons, Ltd.     

云天地表总辐射和净辐射瞬时值的计算方法

为减少计算机时,满足实时预报要求,全球数值预报模式中的辐射计算频率通常设定为三小时。这样处理会大大减少计算量,但也同时导致较大辐射日变化偏差,并影响模式对地面能量平衡,对流及降水的模拟。为改进这一缺陷,我们开发了一种辐射快速计算方案,可用于计算瞬时地面太阳总辐射和净辐射,使到达地面的太阳辐射计算可与模式积分同步进行,从而改善地面太阳辐射日变化模拟。本文介绍云天的计算方法。该方案所用的输入变量均为预报模式或卫星观测所能提供的量。结果表明：该方案既可用于数值预报模式也可利用观测资料独立计算地面太阳辐射。经与美国能源部大气辐射观测资料检验,该方案的精度很高,地面总辐射瞬时值的平均计算误差小于7%。     

偶极声源在裸眼井及套管井外的横波辐射特征

偶极横波远探测技术作为近年来发展起来的一门地球物理测井技术,一个重要应用前景就是在裸眼井和套管井测井时寻找井外地层中的油气构造.本文从井中偶极声场积分表达式的远场渐近解出发,对裸眼井及套管井中偶极声源的辐射场进行了对比分析,首次得到了偶极声源在不同声源频率和不同地层类型下的辐射特征.并深入研究了套管井中偶极声源的SH横波远场辐射特性,给出了不同耦合情况下的SH横波远场辐射特性的变化规律,对比了套前套后SH横波远场辐射的异同.结果表明：井中偶极声源的远场辐射特性受声源频率和地层类型影响较大;在套管井中,偶极声源辐射到地层中的横波能量也可以进行远探测,尽管与裸眼井情况相比,辐射能量会有所降低.本文的结果为偶极横波远探测技术的应用提供了理论支持.     

Impact of Different Aerosols on the Evolution of the Atmospheric Boundary Layer

The present work analyzes the effect of aerosols on the evolution of the atmospheric boundary layer (ABL) over Shangdianzi in Beijing.A one-dimensional ABL model and a radiative transfer scheme are incorporated to develop the structure of the ABL.The diurnal variation of the atmospheric radiative budget,atmospheric heating rate,sensible and latent heat fluxes,surface and the 2 m air temperatures as well as the ABL height,and its perturbations due to the aerosols with different single-scattering albedo (SSA) are studied by comparing the aerosol-laden atmosphere to the clean atmosphere.The results show that the absorbing aerosols cause less reduction in surface evaporation relative to that by scatting aerosols,and both surface temperature and 2 m temperature decrease from the clean atmosphere to the aerosol-laden atmosphere.The greater the aerosol absorption,the more stable the surface layer.After 12:00 am,the 2 m temperature increases for strong absorption aerosols.In the meantime,there is a slight decrease in the 2 m temperature for purely scattering aerosols due to radiative cooling.The purely scattering aerosols decrease the ABL temperature and enhance the capping inversion,further reducing the ABL height.     

The Effects of Different HITRAN Versions on Calculated Long-Wave Radiation and Uncertainty Evaluation

Four editions of the High Resolution Transmission (HITRAN) databases (HITRAN96, HITRAN2K, HITRAN04, and HITRAN08) are compared by using a line-by-line (LBL) radiative model in the long-wave calculation for six typical atmospheres. The results show that differences in downward radiative fluxes between HITRAN96 and HITRAN08 at the surface can reach a maximum of 1.70 W m 2 for tropical atmospheres. The largest difference in heating rate between HITRAN96 and HITRAN08 can reach 0.1 K day 1 for midlatitude summer atmosphere. Uncertainties caused by line intensity and air-broadened halfwidths are also evaluated in this work using the uncertainty codes given in HITRAN08. The uncertainty is found to be 1.92 W m 2 for upward fluxes at the top of the atmosphere (TOA) and 1.97 W m 2 for downward fluxes at the surface. The largest heating rate caused by the uncertainty of line intensity and air-broadened half-width can reach 0.5 K day 1 . The differences in optical depths between 1300 and 1700 cm 1 caused by different HITRAN versions are larger than those caused by the uncertainties in intensity and air-broadened half-width. This paper suggests that there is inaccurate representation of line parameters over some spectral ranges in HITRAN and more attention should be paid to these ranges in fields such as remote sensing.     

玉树站太阳总辐射变化特征及对气候变化的影响

对玉树站1961—2010年实测太阳总辐射资料分析表明,玉树太阳总辐射50年来呈逐渐减少的趋势.方差分析表明,玉树站的太阳总辐射突变点出现在1978年,此前总辐射量呈增加趋势,1978年以后,总体呈减少趋势,太阳总辐射处于相对偏少的时段,突变年后比突变年前平均年总辐射量减少了583.89 MJ/m².玉树各月总辐射减少幅度各不同,8月减少幅度最大,6月减少幅度最小.日照时数的变化趋势与太阳总辐射的变化趋势一致.分析其对气候的影响可知,玉树站总辐射和年平均气温、夏季降水量、年蒸发量均呈负相关.若总辐射减少100 MJ/(m²·a),年平均气温将升高0.03 ℃,5—9月降水量将增加3.0 mm,年蒸发量将增加21.0 mm.     

脉冲星射电轮廓中高斯成分在主脉冲和中间脉冲的不同分布

研究了高斯辐射成分在可视点所画出轨迹上的分布,这个可视点因脉冲星的转动而作非匀速度运动.通过假设辐射区域围绕磁轴均匀分布,一个高斯辐射成分便对应于可视轨迹划过的一个辐射区域.因为演示辐射区域在可视轨迹上是不均匀的分布,因此高斯成分沿轨迹也是不均匀的,而高斯成分的密度在磁轴与视线距离最近时为最大.高斯成分的分布取决于脉冲星的两个角度:旋转轴和视线之间的夹角,以及磁轴和旋转轴之间的倾角.基于此模型,一个脉冲星平均轮廓中观察到的多个高斯成分便对应于可视轨迹在特定的转动相位范围内的辐射区域.演示了脉冲星旋转的近侧和远侧的相位,分别对应的主脉冲和中间脉冲,两者高斯成分的数量和分布是不同的.而且还发现,沿可视轨迹上的辐射区域总数与围绕磁轴的辐射区域的总数是不同,并且预测的辐射区域数目会因忽略可见点的运动而明显不同.拟合表明脉冲星轮廓的高斯成分的形状和数量可能与实际构成轮廓的成分的形状和数量不同.以PSR B0826–34的辐射为例,并假设辐射来自单一磁极.     

IAP AGCM中短波辐射方案的改进研究Ⅱ.短波辐射方案的改进

在Version 2的基础上,对短波辐射方案进行进一步的改进:引入了新增非灰体气体吸收效应、冰晶粒子形状效应和尺度效应以及云的不均匀性效应(称为Version 3).数值模拟试验结果表明:Version 3能更好地模拟出全球冬、夏季的降水场、海平面气压场及地表气温场的主要分布特征,并且能相当准确地反映出这几个场的季节性变化特征.Version 3对这3个场的模拟能力明显优于原版本(Version 1).此外,它对东亚地区的季风降雨具有很好的模拟能力,能较好地反映东亚区域降水的季节性变化.可见,Version 3为进一步研究云-辐射相互作用提供了很好的模式基础.本工作还清楚地表明,模式的进一步发展必须进行对相关物理过程中各个因子的更精确刻画,只有这样,模式才能得到更好的模拟能力.     

一种辐射成像三维可视化系统的实现

辐射成像技术在医疗诊断、无损检测和工业探伤领域有着重要的应用,三维可视化技术与辐射成像技术的结合有助于帮助人们以更直观和形象的方式对病灶和被检物进行检查,从而提供更为有效的信息和检查结果。本文介绍了一种基于辐射数据而构建的三维可视化系统的实现,通过系统分析和整体设计,模块级的实现、交互控制和界面设计等四个方面阐述了基本思路,对于辐射成像可视化系统的研究有一定的借鉴意义。