MM5中新显式云物理方案的建立和数值模拟

在MM5动力框架内, 在其中Reisner 2方案基础上采用双变参数方案, 增加了云水、雨水、雪和霰的数浓度预报方程.云中凝结核CCN的数浓度采用超几何函数表示; 云水向雨水的自动转换过程考虑了云滴谱的特征和发展变化对该过程的影响, 而不是采用原方案给定阈值的方法描述该过程; 对连续碰并方程不再将粒子落速差作为常量提出积分号外, 而是直接作为粒子直径函数在积分号内求解, 这样处理可以回避使用粒子群的平均落速带来的误差; 增加了霰和雪、霰和冰晶的碰并微物理过程.粒子引入Г分布谱函数, 对微物理过程采用了与之     

新疆区域CRA40地面气温检验分析

将高空间分辨率的CRA40地面日平均气温插值到新疆区域105站,以105站实测气温为基准,用平均误差(ME)、均方根误差(RMSE)和相关系数(r)3项检验指标,对新疆区域CRA40地面气温数据质量进行评估,与ERA5气温检验结果进行比较。结果表明：(1)1981—2020年,新疆区域105站CRA40日平均气温与测站实况之间的相关系数r_CRA40为0.973,通过0.001的显著性水平检验。新疆区域CRA40气温与实况比较,日平均气温的年平均值、年最大值和最小值分别相差0.12、0.02和1.94℃,日平均气温年最大、最小值出现日期完全一致。(2)逐年检验结果中,2004年之前ME_CRA40为负偏差,2005年之后为正偏差,无论是ME_CRA40和RMSE_CRA40还是R_CRA40,都反映出2005—2020年新疆区域CRA40气温数据质量有所改进,较前期更加接近ERA5。(3)逐月检验结果中,新疆区域ME_CRA40绝对值和RMSE_CRA40     

对IPCC第五次评估报告减缓气候变化国际合作评估结果的解读

IPCC第五次评估报告第三工作组报告首次对减缓气候变化国际合作进行了独立成章的评估。主要结论认为,《联合国气候变化框架公约》依然是国际合作主要多边论坛,但对该《公约》基本原则的理解出现分歧,《京都议定书》的表现不尽如人意;目前国际合作机制在架构和参与主体方面日趋多元化;国际合作所面临的主要问题是参与度不够、遵约机制不健全。一个“自下而上”的全球协议、资金和技术激励可以促进广泛参与,贸易措施的介入可以完善气候政策、促进参与和遵约,《公约》外的各种小多边主义通过对接可对《公约》机制起到良好的补充作用。这些评估结论可能对2020年后应对气候变化国际合作产生重要影响。     

包含“开关”变量的MM5四维变分资料同化系统

数值模式中的湿物理过程对于模拟各种尺度的天气现象非常重要,但它会使得模式方程的状态变量不连续,这种不连续在模式程序中表现为“开关”变量。本文对包括Kuo降水参数化方案的非静力中尺度数值模式MM5的四维变分资料同化系统进行研究,利用对实际降水的模拟,比较详细地讨论了有关的“开关”变量以及切向线性化和伴随问题。结果表明：对于一个离散的数值模式,保持“开关”变量与基态一致,用伴随码方法构造的伴随模式计算的梯度值能够为最小化过程提供较好的下降方向;Kuo方案中对流每隔一个积分步的交替发生并不影响目标函数最小化的收敛速度;“开关”变量的存在也不影响将风、温度、气压和比湿结合起来同化对MM5降水预报准确性的提高。     

数值预报产品检验和评估

通过国家级数值预报T213模式、EC模式下发产品对影响海南的热带气旋主观性检验结果表明,T213模式不管是对稳定路径还是转折路径的热带气旋在生成、移动路径以及登陆点都与实况相差很大;而EC模式对不管是转折还是稳定路径的热带气旋,都能够对移动路径、登陆点以及转折点都能够做出准确的预报;而在客观性检验的结果中也可看出T213模式和EC模式的预报能力的优劣性。因此,总体来说,在热带气旋的数值预报产品中,EC模式的预报能力明显比T213模式强,具有很高的参考意义。另外在温度场的预报中,T213模式相对于MM5模式,其预报能力具有一定的可信度,在日常预报中具有参考价值。     

Distribution of Delphinidae (Cetacea) in relation to sea surface temperatures off Eastern and Southern New Zealand

Records of four species of Delphinidae, Delphinus delphis, Lissodelphis peroni, Lagenorhynchus obscurus, and Lagenorhynchus cruciger in waters to the east and south‐east of New Zealand are discussed in relation to surface temperatures.

In this region D. delphis appears to be largely confined north of the Subtropical Convergence and a minimum surface temperature of about 14°c, and near New Zealand from Hawke Bay southward in the warm water of the East Cape Current; L. peroni to the Subtropical Convergence and the subantarctic water to the south of it, between surface temperatures of 9°c and 16°c; L. obscurus to the immediate vicinity of the Subtropical Convergence and surface temperatures in summer of about 14° to 15°c, and L. cruciger across the Antarctic Convergence region, in a surface temperature range of 2° to 9°c.     

Mean sea level and the marine geoid—an analysis of concepts

The current ambition to achieve a 10‐cm marine geoid focuses attention on the interdisciplinary problem of relating oceanographic to geodetic measurements, and on the apparent conflict between them along the United States’ coasts. The concepts underlying the comparisons in this conflict are analyzed, and shown to leave a possibility of diffusing the deadlock by more precise reformulations. Concepts which have been equated in practical applications under less stringent accuracy requirements need to be refined and related more precisely through interdisciplinary efforts. An example is given of a geodetic utilization of density differences in the ocean, akin to but not the same as the idea of steric leveling, in order to highlight the similarity and dissimilarity between some geodetic and oceanographic ideas.     

遥感影像邻近效应的实测数据校正（Ⅱ）

本文在总结2004年工作的基础上,以辐射传输理论为基础,改进和增加了地面同步测量邻近效应模型设计和测量参数,实现了航空和卫星数据获取过程的地面同步参数测量。在此基础上,分别对航空ADS40和Landsat-5 TM数字影像进行了邻近效应校正实验,特别对城区ADS40数字影像大气校正和邻近效应校正后的图像做了对比,邻近效应校正的图像较只做大气校正的图像像元值反差更大,细节得到更多增强,图像质量得到一定程度提高。     

老挝铁矿成矿类型及找矿方向

老挝铁矿分为矽卡岩型、热液型和火山喷发—沉积型,尤以北部川圹—万荣一带最丰富。受岛弧-裂谷构造岩浆带控制,北部仍是找矿远景区。     

Projections of hydrology in the Tocantins-Araguaia Basin,Brazil: uncertainty assessment using the CMIP5 ensemble

ABSTRACT

A semi-distributed hydrological model is developed, calibrated and validated against unregulated river discharge from the Tocantins-Araguaia River Basin, northern Brazil. Climate change impacts are simulated using projections from the 41 Coupled Model Intercomparison Project Phase 5 climate models for the period 2071–2100 under the RCP4.5 scenario. Scenario results are compared to a 1971–2000 base line. Most climate models suggest declines in mean annual discharge although some predict increases. A large proportion suggest that the dry season experiences large declines in discharge, especially during the transition to the rising water period. Most models (>75%) suggest declines in annual minimum flows. This may have major implications for both current and planned hydropower schemes. There is greater uncertainty in projected changes in wet season and annual maximum discharges. Two techniques are investigated to reduce uncertainty in projections, but neither is able to provide more confidence in the simulated changes in discharge.

Editor D. Koutsoyiannis Associate editor F. Hattermann