民勤干旱区冬季浓雾形成的边界层条件分析

利用民勤县气象站过程地面小时观测资料、逐日08时和20时每隔50 m探空资料和NECP再分析资料,对2015年11月9—13日出现在干旱区民勤县的一次罕见浓雾天气过程进行了研究分析。结果表明:前期降水后地面相对湿度增大,为大雾形成提供了必要的水汽条件,稳定的高低层环流配置提供了大雾形成的稳定层结和弱风条件。雾层的厚度和强度与近地面逆温层的强度和厚度、边界层高度、水汽垂直运动以及夜间地气温差绝对值密切相关,边界层高度越高,逆温层越厚,雾层越厚;逆温层越强,夜间地气温差绝对值越小,雾层越强。高空环流形势稳定少动,近地层强逆温层、稳定等温层以及饱和湿层长时间维持,导致此次大雾强度和持续时间异常罕见。     

基于生境质量的城市增长边界研究——以长三角地区为例

基于“生态优先”理念,提出一种利用生境质量评估策略的城市增长边界划定方法。结合ArcGIS和InVEST模型,通过综合评估生境自身及其在威胁情境下的质量,模拟各市独立规划、建设用地指标再分配及区域一体化发展的三类建设用地扩张情景,分别划定2024和2034年的长三角地区城市增长边界。结果表明：研究区生境质量总体呈南高北低格局,平均生态系统服务价值密度为10 770.604元/（hm²·a）,高质生境位于西南地区;根据指标再分配及一体化发展情景模拟的2024年研究区建设用地总量分别为10 583.273 km2和10 489.090 km2,2034年达到13 603.535 km2和13 252.370 km2;模拟的建设用地集中在东部沿海地区,并向北部及环杭州湾区域拓展;建设用地指标再分配能从整体上减少建设用地对优质生境的占用,区域一体化发展则能进一步降低城市发展造成的生态压力。     

An Assessment of HOx Chemistry in the Tropical Pacific Boundary Layer: Comparison of Model Simulations with Observations Recorded during PEM Tropics A

Reported are the results from a comparison of OH,H₂O₂CH₃OOH, and O₃ observationswithmodel predictions based on current HO_x–CH₄reaction mechanisms. The field observations are thoserecorded during the NASA GTE field program, PEM-Tropics A. The major focus ofthis paper is on thosedata generated on the NASA P-3B aircraft during a mission flown in the marineboundary layer (MBL) nearChristmas Island, a site located in the central equatorial Pacific (i.e.,2° N, 157° W). Taking advantage of thestability of the southeastern trade-winds, an air parcel was sampled in aLagrangian mode over a significantfraction of a solar day. Analyses of these data revealed excellent agreementbetween model simulated andobserved OH. In addition, the model simulations reproduced the major featuresin the observed diurnalprofiles of H₂O₂ and CH₃OOH. In the case ofO₃, the model captured the key observational feature whichinvolved an early morning maximum. An examination of the MBL HO_xbudget indicated that the O(¹D) + H₂Oreaction is the major source of HO_x while the major sinks involveboth physical and chemical processes involving the peroxide species,H₂O₂ and CH₃OOH. Overall, the generally goodagreement between modeland observations suggests that our current understanding ofHO_x–CH₄ chemistry in the tropical MBL isquite good; however, there remains a need to critically examine this chemistrywhen both CH₂O and HO₂are added to the species measured.     

An Actively Controlled Wind Tunnel And Its Application To The Reproduction Of The Atmospheric Boundary Layer

An actively controlled wind tunnel equipped with multiple fansand airfoils has been developed, mainly for the purpose of reproducing the atmospheric boundary layer (ABL) for wind engineering applications. Various fluctuating flows can be achieved in this wind tunnel by altering the input data of the fans and airfoils through computer control. In this study, the ABL is physically simulated in this wind tunnel, and particular attention ispaid to the simulation of the profile of Reynolds stress. The method of generating the fluctuating flow and the experimental results of reproducing the ABL are presented. As the results show, the spatial distribution of Reynolds stress is satisfactorily simulated, and the profiles of other statisticalturbulent parameters, such as mean velocity, turbulent intensity, integral scale and power spectrum are successfully reproduced simultaneously.     

Isoprene and Its Oxidation Products Methyl Vinyl Ketone, Methacrolein, and Isoprene Related Peroxides Measured Online over the Tropical Rain Forest of Surinam in March 1998

Airborne measurements of volatile organic compounds (VOC) were performed overthe tropical rainforest in Surinam (0–12 km altitude,2°–7° N, 54°–58° W) using the proton transferreaction mass spectrometry (PTR-MS) technique, which allows online monitoringof compounds like isoprene, its oxidation products methyl vinyl ketone,methacrolein, tentatively identified hydroxy-isoprene-hydroperoxides, andseveral other organic compounds. Isoprene volume mixing ratios (VMR) variedfrom below the detection limit at the highest altitudes to about 7 nmol/molin the planetary boundary layer shortly before sunset. Correlations betweenisoprene and its product compounds were made for different times of day andaltitudes, with the isoprene-hydroperoxides showing the highest correlation.Model calculated mixing ratios of the isoprene oxidation products using adetailed hydrocarbon oxidation mechanism, as well as the intercomparisonmeasurement with air samples collected during the flights in canisters andlater analysed with a GC-FID, showed good agreement with the PTR-MSmeasurements, in particular at the higher mixing ratios.Low OH concentrations in the range of 1–3 × 10⁵molecules cm^-3 averaged over 24 hours were calculated due to lossof OH and HO₂ in the isoprene oxidation chain, thereby stronglyenhancing the lifetime of gases in the forest boundary layer.     

非等时空距GM(1,1)模型在建筑物沉降预测中的应用

以灰色理论为指导，GM（1，1）模型为基础，提出用最小二乘原理对灰色模型进行优化，大大提高非等时距GM（1，1）模型的预测精度，并对某海堤监测数据进行预报，检验结果表明预测值达到很好精度，由此证明，此方法有较大的应用价值。     

塔河油田下奥陶统溶蚀段的测井响应

塔河油田位于塔里木盆地，为该盆地油气中储量最大，产量最高的油田。下奥隐统是塔河油田最重要的储集层段，而下奥陶统中溶蚀成因的孔洞又是该层段最主要的储集空间。通过对该溶蚀段的研究，笔者认为该溶蚀段具有可以识别的测井响应，其密度呈指状急剧降低，是溶蚀段最明显的特征，并以此与中上奥陶统的瘤状灰岩形成明显区别。     

潍北凹陷中新生代层序地层的沉积模式

潍北凹陷是受郯庐断裂带直接控制而发育起来的一个小型中新生代富含油气沉积盆地。根据财震反射界面特征，在凹陷孔店组和沙四段（沙河街组四段）内鉴别出6个地震层序界面，进而划分为5个三级层序。在分析初始湖泛面和最大湖泛面的基础上，对层序内体系域和沉积特征进行了划分与分析。盆地沉积演化可划分为开裂期，早期沉降，再沉降，早期萎缩和晚期沉降五个阶段，并对凹陷内两种层地层的沉积模式进行了总结。     

Development of garnet porphyroblasts by multiple nucleation,coalescence and boundary misorientation‐driven rotations

Two types of garnet porphyroblast occur in the Schneeberg Complex of the Italian Alps. Type 1 porphyroblasts form ellipsoidal pods with a centre consisting of unstrained quartz, decussate mica and small garnet grains, and a margin containing large garnet grains. Orientation contrast imaging using the scanning electron microscope shows that the larger marginal garnet grains comprise a number of orientation subdomains. Individual garnet grains without subdomains are small (< 50 µm), faceted and idioblastic, and have simple zoning profiles with Ca‐rich cores and Ca‐poor rims. Subdomains of larger garnet grains are similar in size to the individual, small garnet grains. Type 2 porphyroblasts comprise only ellipsoidal garnet, with small subdomains in the centre and larger subdomains at the margin. Each subdomain has its own Ca high, Ca dropping towards subdomain boundaries. Garnet grains, with or without subdomains, all have the same Ca‐poor composition at rims in contact with other minerals. The compositional zonation patterns are best explained by simultaneous, multiple nucleation, followed by growth and amalgamation of individual garnet grains. The range of individual garnet and garnet subdomain sizes can be explained by a faster growth rate at the porphyroblast margin than in the centre. The difference between Type 1 and Type 2 porphyroblasts is probably related to the growth rate differential across the porphyroblast. Electron backscatter diffraction shows that small, individual garnet grains are randomly oriented. Large marginal garnet grains and subdomain‐bearing garnet grains have a strong preferred orientation, clustering around a single garnet orientation. Misorientations across subdomain boundaries are small and misorientation axes are randomly oriented with respect to crystallographic orientations. The only explanation that fits the observational data is that individual garnet grains rotated towards coincident orientations once they came into contact with each other. This process was driven by the reduction of subdomain boundary energy associated with misorientation loss. Rotation of garnet grains was accommodated by diffusion in the subdomain boundary and diffusional creep and rigid body rotation of other minerals (quartz and mica) around the garnet. An analytical model, in which the kinetics of garnet rotation are controlled by the rheology of surrounding quartz, suggests that, at the conditions of metamorphism, the rotation required to give a strong preferred orientation can occur on a similar time‐scale to that of porphyroblast growth.     

Curved scanline theory

This work develops the theory of measuring fracture frequency with curved scanlines, as a direct development of work done by others on straight scanlines. Various possible shapes for curved scanlines range between triangular and rectangular, with circular as a reasonable preliminary selection. The discrepancy among different selections decreases with increasing roughness amplitude of the scanline. Analytic solutions for average fracture frequency are given for circular scanlines through single and multiple fracture sets. Results for single fracture sets are plotted. The analytic solution for the general situation of any shape scanline through multiple fracture sets is given. Analytic solutions are given and plotted for circular scanlines through a fracture fabric ellipsoid. A circular scanline spanning 180 degrees yields a global fracture frequency of statistical significance. This work was carried out under U.S. Department of Energy Contract No. DEAC03-76SF00098 for the Director, Office of Civilian Radioactive Waste Management, Office of External Relations, and was administered by the Nevada Operations Office, U.S. Department of Energy. This work also was supported partially by the Power Reactor and Nuclear Fuel Development Corporation of Japan.