Stratosphere amplifies the global climate effect of wildfires

The summer of 2019 witnessed a great number of wildfires around the globe.For example,wildfires scorched huge swaths of Alaska,British Columbia in Canada,and parts of Greenland.And forest fires in Siberia and the Far East of Russia were also very serious,affecting nearly 3 million hectares of land,and putting some parts of Russia into a state of emergency.In particular,forest fires in the Amazon region had attracted global attention.According to Science,as of August 24,BraziPs National Institute for Space Research had counted more than 41000 fires this year,86%more than last year,compared with 22000 in the same period last year.Scientists in Brazil and elsewhere believe that the recent increase of wildfires is closely related to the increasing ac・tivities of deforestation(Arruda et al.,2019;Escobar,2019).     

山西省县域经济发展差异的时空演化分析

利用核密度估计方法和探索性空间数据分析方法,以山西省107个县域为基本的研究对象,采用2000-2011年的县域人均GDP数据,定量分析了这12年间山西省县域经济的时变特征、空间相关性及其演化趋势.结果显示:山西省县域经济发展总体水平较低,县域经济发展差异显著;晋南地带的经济发展水平明显高于晋北和晋中地带,县域经济发展表现出一定程度的集聚,但远未形成能够带动县域经济发展的稳定的核心区域.在晋北和晋中地带没有出现以大同、太原等盆地县域为中心的带动经济发展的核心县域集聚群,仅在晋南地带出现了以临汾等盆地县域为中心的较高发展水平的县域集聚群;县域经济增长的热点区域自2004年趋于消失,县域经济增长的空间差异比较突出,没有形成增长集聚区域.     

Comparative Analysis of Mitochondrial Control Region Sequence from Three Flatfish Species （Pleuronectidae）

The 5‘-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phylogenetic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5‘-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were identified at the 5‘-end of the sequences. A conserved sequence block, named as CM5‘ d, was identified in the 5‘-end of control region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.     

不同对流参数化方案试验中凝结加热的特征及对暴雨中尺度模拟结果的影响

使用20 km分辨率的MM5模式,分别选用KUO,GRELL,KAIN-FRITSCH和BETTS-MILLER(以下简称KU,GR,KF和BM)等4种不同对流参数化方案,对1996年8月3~4日石家庄特大暴雨过程作数值模拟试验,分析比较了4个不同试验中网格尺度(显式方案)和次网格尺度(对流参数化方案)凝结加热的水平、垂直分布和时变特征;研究探讨了凝结加热分布及差异对暴雨中尺度模拟结果的可能影响。分析显示,暴雨过程中,4个不同对流参数化方案试验所得到的次网格尺度凝结加热基本都呈单峰特征、加热峰值在对流层中层,但加热层厚度和强度在不同试验间存在差别;4个试验的网格尺度凝结加热的垂直范围表现出较好的一致性,加热重心位于对流层低层,但加热强度仍有所不同;GR和KF及BM试验的总凝结加热率的垂直分布特征主要受其网格尺度凝结加热率特征的影响、加热重心在对流层低层,而KU试验的总凝结加热率的垂直分布特征由其次网格尺度凝结加热率特征所决定、加热重心在对流层中层。研究表明,尽管4个试验在暴雨期间总凝结加热的垂直分布差异并不显著,但对暴雨中尺度模拟的影响却不能忽视。凝结加热的分布特征及演变直接影响与暴雨发生发展密切关联的物理量场的中尺度结构和演变;凝结加热对暴雨中尺度的影响具有连锁性,由加热差异波及局部环流细致结构和强度及其变化的差异,进而影响暴雨发生发展的细致特征。在20 km或更高一些分辨率的条件下,对于描述温带/中纬度暴雨的发展和结构,选用KF方案得到的模拟结果可能更具物理合理性;而KU方案模拟结果容易出现格点气柱的水汽和温度被过量调整的不合理情况。要得到一个可信的中尺度模拟结果,对降水模拟结果进行细化特征的验证、特别是随时间演变特征的验证分析是非常重要的,因为降水的细致演变特征与凝结加热及与之相联系的物理量场的中尺度演变特征密切关联。     

THE INTERACTION BETWEEN EDDY FLUX AND ZONAL AVERAGED FLOW IN“JUNE SUDDEN CHANGE”

In this paper,Eliassen-Palm theory and associated diagnostic method are used to discuss the dynamicalmechanism of the interaction between eddy flux and zonal averaged flow in the sudden change of the generalcirculation in the Northern Hemisphere in early summer of 1982,which indicates that the northward jump ofsubtropic jet stream is closely related to the enhanced transport of mid-latitude eddy energy to the subtropic tro-popause.However,the direction of the transport is conditioned by the structure of zonal averaged flow.It isevident that the adjustment of zonal averaged flow responses quickly to the eddy transport during this episode.As regard to the suddenness of the change of circulation,the critical role is played by the eddy forcing,     

青藏高原夏季上空水汽含量演变特征及其与降水的关系(英文)

By using the observed monthly mean temperature and humidity datasets of 14 radiosonde stations and monthly mean precipitation data of 83 surface stations from 1979 to 2008 over the Tibetan Plateau(TP),the relationship between the atmospheric water vapor(WV) and precipitation in summer and the precipitation conversion efficiency(PEC) over the TP are analyzed.The results are obtained as follows.(1) The summer WV decreases with increasing altitude,with the largest value area observed in the northeastern part of the TP,and the second largest value area in the southeastern part of the TP,while the northwestern part is the lowest value area.The summer precipitation decreases from southeast to northwest.(2) The summer WV presents two main patterns based on the EOF analysis:the whole region consistent-type and the north-south opposite-type.The north-south opposite-type of the summer WV is similar to the first EOF mode of the summer precipitation and both of their zero lines are located to the north of the Tanggula Mountains.(3) The summer precipitation is more(less) in the southern(northern) TP in the years with the distribution of deficient summer WV in the north while abundant in the south,and vice versa.(4) The PEC over the TP is between 3% and 38% and it has significant spatial difference in summer,which is obviously bigger in the southern TP than that in the northern TP.     

Predicting rock size distribution in mine blasting using various novel soft computing models based on meta-heuristics and machine learning algorithms

Blasting is well-known as an effective method for fragmenting or moving rock in open-pit mines. To evaluate the quality of blasting, the size of rock distribution is used as a critical criterion in blasting operations. A high percentage of oversized rocks generated by blasting operations can lead to economic and environmental damage. Therefore, this study proposed four novel intelligent models to predict the size of rock distribution in mine blasting in order to optimize blasting parameters, as well as the efficiency of blasting operation in open mines. Accordingly, a nature-inspired algorithm (i.e., firefly algorithm – FFA) and different machine learning algorithms (i.e., gradient boosting machine (GBM), support vector machine (SVM), Gaussian process (GP), and artificial neural network (ANN)) were combined for this aim, abbreviated as FFA-GBM, FFA-SVM, FFA-GP, and FFA-ANN, respectively. Subsequently, predicted results from the abovementioned models were compared with each other using three statistical indicators (e.g., mean absolute error, root-mean-squared error, and correlation coefficient) and color intensity method. For developing and simulating the size of rock in blasting operations, 136 blasting events with their images were collected and analyzed by the Split-Desktop software. In which, 111 events were randomly selected for the development and optimization of the models. Subsequently, the remaining 25 blasting events were applied to confirm the accuracy of the proposed models. Herein, blast design parameters were regarded as input variables to predict the size of rock in blasting operations. Finally, the obtained results revealed that the FFA is a robust optimization algorithm for estimating rock fragmentation in bench blasting. Among the models developed in this study, FFA-GBM provided the highest accuracy in predicting the size of fragmented rocks. The other techniques (i.e., FFA-SVM, FFA-GP, and FFA-ANN) yielded lower computational stability and efficiency. Hence, the FFA-GBM model can be used as a powerful and precise soft computing tool that can be applied to practical engineering cases aiming to improve the quality of blasting and rock fragmentation.     

单元畸变对动力有限元方法计算精度的影响

在有限元分析中,由于求解区域或边界的不规则,有限单元的划分会产生畸变单元。本文通过数值试验分析了有限单元畸变对动力有限元计算精度的影响,结果表明:长宽比畸变对动力有限元计算精度没有影响;当斜交角不小于30°时,斜交角对动力有限元计算精度的影响可忽略;锥度对动力有限元计算精度有影响,锥度越大,锥度对动力有限元计算精度的影响越大。     

水电工程坝址区构造应力场三维数值反演

以水电工程实例为背景,在现场调查和地应力测量的基础上,采用三维数值技术对水电站坝址区小范围内构造应力场进行了反演分析,通过对三维模型施加不同量值、不同方向的边界载荷,对比分析应力拟合点处的计算主应力与实测主应力之间的差别,从而得到最合理的边界载荷的量值和方向,即为坝址区构造应力场的量值和方向。计算结果表明：水电站坝址区构造应力场σ₁方向为S50°－60°E,量值为6～7 MPa;σ₃方向为N50°－60°E,量值为3～4 MPa。反演计算得到的坝址区构造应力场方向与区域应力场方向吻合,主应力量值也在合理范围内。     

海平面上升对长江三角洲海堤、航运和水资源的影响

分析了２０５０ 年长江三角洲地区相对海平面上升５０～７０ ｃｍ 时,将对该地区沿海海堤、航运及海岸带水资源的影响,并就相应的适应对策提出了建议。