The Anomalous Mei-yu Rainfall of Summer 2020 from a Circulation Clustering Perspective: Current and Possible Future Prevalence※

Highly unusual amounts of rainfall were seen in the 2020 summer in many parts of China, Japan, and South Korea. At the intercontinental scale, case studies have attributed this exceptional event to a displacement of the climatological western North Pacific subtropical anticyclone, potentially associated Indian Ocean sea surface temperature patterns and a mid-latitude wave train emanating from the North Atlantic. Using clusters of spatial patterns of sea level pressure, we show that an unprecedented 80％ of the 2020 summer days in East Asia were dominated by clusters of surface pressure greater than normal over the South China Sea. By examining the rainfall and water vapor fluxes in other years when these clusters were also prevalent, we find that the frequency of these types of clusters was likely to have been largely responsible for the unusual rainfall of 2020. From two ensembles of future climate projections, we show that summers like 2020 in East Asia may become more frequent and considerably wetter in a warmer world with an enhanced moisture supply.     

The Demographic Constraints on Future Population Growth in Regional Australia

Concern about rapid population growth in Australia's large cities and slower growth in many non-metropolitan areas has stimulated a range of government policies attempting to lift non-metropolitan growth rates. However, there is relatively little research on which to base these policies. It would be helpful to understand more about the consequences of current demographic trends continuing and the effects of alternative migration patterns. This paper presents sub-national population projections for Australia over the horizon 2011–2041, basing the projections on more socially meaningful Remoteness Areas instead of common statistical geographies. Three sets of projections were generated: a Current Direction scenario in which recent demographic trends are maintained, a Regional Immigration scenario in which more immigrants settle in regional and remote areas, and a Metro Exodus scenario in which there is increased internal migration from metropolitan to non-metropolitan areas. The future of Australia's population geography is shown to be one of spatially varying growth and population ageing, and continued metropolitanisation. In regional areas rapid population ageing will lower natural increase rates and thus reduce overall growth, resulting in a falling share of the national population. Policy measures attempting to increase the share of growth in regional areas will struggle against natural demographic forces operating in the opposite direction.     

双投影矩阵模型的方向关系组合推理研究

将三维空间中的参照物体分别向xoy和xoz平面投影,得到的最小外接矩形将两个平面都划分成9个区域,用两个三行三列矩阵联合表示目标物体投影与两个参考区域的相交情况,据此提出了双投影方向关系矩阵模型。基于该模型,利用矩阵的计算性能,提出了一种三维空间方向关系的组合推理方法,解决了方向关系的组合推理问题。     

加权残值法与等角投影数值变换

本文介绍了描述等角投影变换的Dirichlet模型和用加权残值法求解该模型的一般原理和方法,并给出了应用上述方法所获得的某些等角投影变换的数值公式。文章最后指出,由于应用数值方法,有可能形成一门新的学科,即计算地图投影学。     

China’s changing economy and emissions trajectory: following global trends

A key climate policy issue and debate is the future trajectory of emissions of carbon dioxide of countries, their peaking dates, and rates of decline after peaking. This article analyses China’s emissions trajectory in terms of global historical trends distinguishing between industry, infrastructure, and urbanization. Growth of emissions from industrialization and infrastructure development has stabilized in 2014 with saturation levels being reached, while the process of urbanization continues with the shift of the economy to the services sector, with reduced energy use, and this is a global trend. The future trajectory of emissions will be shaped largely by growth of transport and building-related services which directly impact on and are shaped by middle-class levels of well-being. These are areas where convergence with levels of services in other urbanized countries is an important element of national policy. This global trend has not been adequately taken into account in modelling and macroeconomic analysis which ignore social processes. The article concludes that China’s 13th Five Year Plan (2016–2020) seeks to achieve a ‘moderately well-off society’ while putting a cap on total energy demand by modifying the drivers of consumption emissions compared with countries that urbanized earlier. The adoption of a public policy priority of dense mixed-use urban form, public transport, energy efficiency to enable energy system reform, and digital economy could be a model for others.

Policy relevance

The article redefines climate change in terms of social processes as urban form and notions of well-being lock-in increasing levels of future emissions of carbon dioxide. There are implications for research in assessing how best drivers of emissions can be modified without affecting well-being, including renewable and digital technologies and human behaviours that drive patterns of natural resource use as well as the identification of leverage points. There are also broader implications for replacing the development cooperation model of global climate governance to focus on new values recognizing interdependencies for sharing responsibility as well as prosperity.     

A new pseudocylindrical equal-area projection for adaptive composite map projections

The recently introduced adaptive composite map projection technique changes the projection to the geographic area shown on a map. It is meant as a replacement for the commonly used web Mercator projection, which grossly distorts areas when representing the entire world. The original equal-area version of the adaptive composite map projection technique uses the Lambert azimuthal projection for regional maps and three alternative projections for world maps. Adaptive composite map projections can include a variety of other equal-area projections when the transformation between the Lambert azimuthal and the world projections uses Wagner’s method. To select the most suitable pseudocylindrical projection, the distortion characteristics of a pseudocylindrical projection family are analyzed, and a user study among experts in the area of map projections is carried out. Based on the results of the distortion analysis and the user study, a new pseudocylindrical projection is recommended for extending adaptive composite map projections. The new projection is equal-area throughout the transformation to the Lambert azimuthal projection and has better distortion characteristics then small-scale projections currently included in the adaptive composite map projection technique.     

Using response surfaces to estimate impacts of climate change on flood peaks: assessment of uncertainty

The potential impacts of climate change are an increasing focus of research, and ever‐larger climate projection ensembles are available, making standard impact assessments more onerous. An alternative way of estimating impacts involves response surfaces, which present the change in a given indicator for a large number of plausible climatic changes defined on a regular sensitivity domain. Sets of climate change projections can then be overlaid on the response surface and impacts estimated from the nearest corresponding points of the sensitivity domain, providing a powerful method for fast impact estimation for multiple projections and locations. However, the effect of assumptions necessary for initial response surface development must be assessed. This paper assesses the uncertainty introduced by use of a sensitivity framework for estimating changes in 20‐year return period flood peaks in Britain. This sensitivity domain involves mean annual and seasonal precipitation changes, and a number of simplifications were necessary for consistency and to reduce dimensionality. The effect of these is investigated for nine catchments across Britain, representing nine typical response surfaces (response types), using three sets of climate projections. The results show that catchments can have different causes of uncertainty and some catchments have an overall higher level of uncertainty than others. These differences are compatible with the underlying climatological and hydrological differences between the response types, giving confidence in generalization of the results. This enables the development of uncertainty allowances by response type, to be used alongside the response surfaces to provide more robust impact estimates. Copyright © 2013 John Wiley & Sons, Ltd.     

21世纪新疆区域气候暖湿化趋势预估分析

新疆未来暖湿化的预估分析可为区域气候变化减缓和适应提供重要的科学基础。国际耦合模式比较计划第六阶段（CMIP6）全球气候模式在三种共享社会经济路径（SSPs）下的结果显示,新疆地区未来2021~2100年总体呈现气温升高、降水增加的“暖湿化”现象,但这种变化的具体数值和空间分布存在一定差异。其中SSP2-4.5情景下,相对于1995~2014年,预估2021~2040年新疆地区年平均气温将升高1.2℃左右,年平均降水将增加6.8%。对极端事件的预估结果表明,新疆地区未来暖事件将增加,冷事件将减少;极端强降水事件将增多,且高排放情景下的增加更为显著。新疆地区的未来预估分析,将有助于对新疆地区灾害风险时空变化格局的认识,对未来农业方面等风险防范也有重要的指示作用。     

The impact of climate change on U. K. river flows: A preliminary comparison of two generations of probabilistic climate projections

The impacts of climate change on future river flows are a growing concern. Typically, impacts are simulated by driving hydrological models with climate model ensemble data. The U.K. Climate Projections 2009 (UKCP09) provided probabilistic projections, enabling a risk-based approach to decision-making under climate change. Recently, an update was released—UKCP18—so there is a need for information on how impacts may differ. The probabilistic projections from UKCP18 and UKCP09 are here applied using the change factor method with catchment-based hydrological modelling for 10 catchments across England. Projections of changes in median, mean, high, and low flows are made for the 2050s, using the A1B emissions scenario from UKCP09 and UKCP18 as well as the RCP4.5 and RCP8.5 emissions scenarios from UCKP18. The results show that, in all catchments for all flow measures, the central estimate of change under UKCP18 is similar to that from UKCP09 (A1B emissions). However, the probabilistic uncertainty ranges from UKCP18 are, in all cases, greater than from UKCP09, despite UKCP18 having a smaller ensemble size than UKCP09. Although there are differences between the central estimates of change using UKCP18 RCP4.5, RCP8.5 and A1B emissions, there is considerable overlap in the uncertainty ranges. The results suggest that existing assessments of hydrological impacts remain relevant, though it will be necessary to evaluate sensitive decisions using the latest projections. The analysis will aid development of advice to users of current guidance based on UKCP09 and help make decisions about the prioritization of further hydrological impacts work using UKCP18, which should also apply other products from UKCP18 like the 12-km regional data.     

Accurate area determination in the cadaster: case study of Slovenia

This paper discusses methodological problems of accurate area determination in the cadaster. The paper contrasts the ambiguous legal definition of the parcel boundary and parcel area in relation to the theoretically well-defined geodetic parcel boundary and the geodetic parcel area on the reference ellipsoid. To align with the real world, parcel area must account for terrain elevation. Various approximate methods for area determination which can be used in the cadaster are tested. A highly accurate method for parcel area computation is proposed, based on an equal-area projection. Considering the geodetic parcel area as a reference, the achievable accuracy of different methods is evaluated. For this analysis, the coordinates of the parcel boundary points are treated as error-free. Finally, the relevance of various systematic errors is discussed in relation to the statistical uncertainty of the parcel area, which could be gained by an a real-time kinematic GNSS survey. A case study is presented for the territory of Slovenia, its georeferencing rules, land demarcation pattern, and characteristics of its topography. Based on the results of this study, some general recommendations for the parcel area determination are given.