末次间冰期127 ka时期植被反馈增强东亚夏季风降水的数值模拟研究

黄土和石笋等古气候代用资料表明在末次间冰期间,东亚夏季风增强、降水增多。本研究利用地球系统模式EC-Earth模拟了末次间冰期127 ka时期的气候,通过和工业革命前的气候模拟控制试验做比对,分析了127 ka时期由于地球轨道参数变化导致的东亚夏季风的空间变化特征。我们利用了两种EC-Earth的模式配置,即"大气-陆面-海洋-海冰"耦合模式和"大气-陆面-海洋-海冰-动态植被"耦合模式,分别估算轨道强迫和植被反馈对东亚夏季风降水变化的贡献。数值模拟结果表明,地球轨道强迫导致的海陆热力差异使得东亚夏季风系统显著增强并北移西伸,中国中部及华北地区降水增多而东部沿海地区降水减少。耦合了动态植被模式的试验结果表明,127 ka时期温暖湿润的气候致使东亚地区植被增多,植被的蒸腾作用使得地表的感热和潜热通量显著增大,从而增强了局地水循环,使降水进一步增多。植被的反馈作用在原本温暖湿润的华南地区对降水的影响并不显著,但是对相对干旱的我国中部和华北地区降水有显著影响。数值试验结果表明轨道强迫和植被反馈的共同作用能使内陆的四川盆地到华北一带夏季降水增加约40%,其中30%的增加是由于轨道强迫作用,约10%是由于植被反馈。这个研究也提醒我们,要得到更加合理的对过去或未来气候变化的模拟结果,有必要使用耦合动态植被的气候系统模式。

     

Understanding the implications of the EU-LULUCF regulation for the wood supply from EU forests to the EU

Background

In June 2018, the European Parliament and Council of the European Union adopted a legislative regulation for incorporating greenhouse gas emissions and removals from Land Use, Land Use Change and Forestry (EU-LULUCF) under its 2030 Climate and Energy Framework. The LULUCF regulation aim to incentivise EU Member States to decrease greenhouse gas emissions and increase removals in the LULUCF sector. The regulation, however, does not set a target for increasing the LULUCF carbon sink, but rather includes a ‘no net debit’ target for LULUCF (Forests and Agricultural soils). For Managed Forest Land (MFL) an accounting framework with capped credits for additional mitigation against a set forest reference level (FRL) was agreed for 2021–2030. The FRL gives the projected future carbon sink in the two compliance periods 2021–2025 and 2026–2030 under “continuation of forest management practices as they were in the reference period 2000–2009”. This FRL was disputed by some Member States as it was perceived to put a limit on their future wood harvesting from MFL. Here we simulated with the EFISCEN European forest model the “continuation of forest management practices” and determined the corresponding wood harvest for 26 EU countries under progressing age classes.

Results

The simulations showed that under “continuation of forest management practices” the harvest (wood removals) in the 26 EU countries as a whole can increase from 420 million m³/year in 2000–2009 to 560 million m³/year in 2050 due to progressing age classes. This implies there is a possibility to increase absolute wood harvests without creating debits compared to the forest reference level. However, the manner in which ‘continuation of forest management’ developed with a progressing age class development over time, meant that in some countries the future harvesting exceeded 90% of the increment. Since this generally is considered to be unsustainable we additionally set a harvesting cut-off as max 90% of increment to be harvested for each individual country as a possible interpretation of sustainability criteria that are included in the regulation. Using this additional limit the projected harvest will only increase to 493 million m³/year.

Conclusions

The worry from Member States (MS) that the FRL will prevent any additional harvesting seems unwarranted. Due to differences between Member States concerning the state of their forest resources, the FRL as a baseline for harvesting works out very differently for the different Member States. The FRL may have other unforeseen consequences which we discuss. Under all scenarios the living forest biomass sink shows a decline. This can be counteracted through incentivising measures under Climate Smart Forestry.

     

An improved ant colony optimization (I-ACO) method for the quasi travelling salesman problem (Quasi-TSP)

Traveling salesman problem (TSP) and its quasi problem (Quasi-TSP) are typical problems in path optimization, and ant colony optimization (ACO) algorithm is considered as an effective way to solve TSP. However, when the problems come to high dimensions, the classic algorithm works with low efficiency and accuracy, and usually cannot obtain an ideal solution. To overcome the shortcoming of the classic algorithm, this paper proposes an improved ant colony optimization (I-ACO) algorithm which combines swarm intelligence with local search to improve the efficiency and accuracy of the algorithm. Experiments are carried out to verify the availability and analyze the performance of I-ACO algorithm, which cites a Quasi-TSP based on a practical problem in a tourist area. The results illustrate the higher accuracy and efficiency of the I-ACO algorithm to solve Quasi-TSP, comparing with greedy algorithm, simulated annealing, classic ant colony algorithm and particle swarm optimization algorithm, and prove that the I-ACO algorithm is a positive effective way to tackle Quasi-TSP.     

干旱区工业有害废物处置场的选址及相关问题研究

利用新疆干旱区地理环境、气候特征对工业有害废物填埋处置场的选址、设计特点及安全性预测等问题进行了研究，以某工厂有害废渣填埋处置场为例结合有关固体废物安全填埋研究课题成果，对干旱区与湿润区有害固体废物填埋工作的特点做了分析对比，对填埋处置场（坑）的设计计算及安全性预测等提出了创新的观点和方法．对于在干旱、半干旱区既安全又经济地进行有害废物填埋工作有较高的参考价值．     

The influence of rainfall and land use patterns on soil erosion in multi-scale watersheds: A case study in the hilly and gully area on the Loess Plateau,China

Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau (LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use (LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different- scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor (R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor (C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.     

京津冀及周边一般性降水与短时强降水特征对比

京津冀及周边地区为我国北方强降水的多发区域。基于1966—2021年87个国家级气象站逐小时降水资料对比分析暖季5—9月一般性降水和短时强降水的空间分布及年际变化,并基于1980—2021年298个气象站分析日变化等特征。结果表明：京津冀及周边地区的渤海西侧平原区域存在短时强降水强度极端性显著区域。渤海西侧平原以外区域两类降水平均小时降水量、强度和降水时次百分比均呈增长趋势,但短时强降水的增幅更高,而渤海西侧平原区域趋势则均不明显。渤海西侧平原区域和渤海西侧平原以外区域的一般性降水平均小时降水量和降水时次百分比日变化幅度显著弱于短时强降水;7—9月渤海西侧平原区域降水夜发性更明显,且相比另一区域半峰持续时间多出约2 h。2005年后渤海西侧平原区域和渤海西侧平原以外区域短时强降水平均小时降水量和降水时次百分比下午时段均明显减弱,但午夜后至清晨明显增加。     

福建永安石林地貌的现代生物喀斯特侵蚀营力

本文以永安石林为例，阐述分析了石林地貌的现代生物喀斯特侵蚀现象的类型及形态特征。结果表明，地表及地下的生物喀斯特侵蚀营力是石林现代侵蚀过程的主要因素，石林表面的大部分均有微生物覆盖并起侵蚀作用，形成明显的微观及超微溶蚀形态，石林表面的溶蚀作用性质不同于传统认识。对石林地貌发育提出了新的思考。     

淮河流域水文随机方法的径流图化(英文)

Theoretical difficulties for mapping and for estimating river regime characteristics in a large-scale basin remain because of the nature of the variable under study: river flows are related to a specific area, i.e. the drainage basin, and are hierarchically organized in space through the river network with upstream-downstream dependencies. Another limitation is there are not enough gauge stations in developing countries. This presentation aims at de-veloping the hydro-stochastic approach for producing choropleth maps of average annual runoff and computing mean discharge along the main river network for a large-scale basin. The approach applied to mean annual runoff is based on geostatistical interpolation proce-dures coupled with water balance and data uncertainty analyses. It is proved by an applica-tion in the upstream at Bengbu in the Huaihe River Basin, a typical large-scale basin in China. Hydro-stochasitic approach in a first step interpolates to a regular grid net and in a second step the grid values are integrated along rivers. The interpolation scheme includes a con-straint to be able to account for the lateral water balance along the rivers. Grid runoff map with 10 km × 10 km resolution and the discharge map along the river with the 1 km basic length unit are the main results in this study. This kind of statistic approach can be widely used be-cause it avoids the complexity of hydrological models and does not depend on the meteoro-logical data.