大气臭氧与气溶胶垂直分布的高空气球探测   总被引：17，自引：2，他引：17  

石广玉  许黎  郭建东  张豹武  孙宝来  龚知本  周军  谭锟  岩坂泰信  林政彦  长谷正博 《大气科学》1996,20(4):401-407

本文给出了1993年9月12日利用高空科学气球在河北省香河地区探测到的大气臭氧和气溶胶的垂直分布。结果发现:(1) 大气臭氧的数密度在整个对流层较低(～10[12]mol/cm3)，并从地面到对流层顶略有下降；对流层顶以上开始快速增加，极值层高度在～24 km，其值为4.78×10[12]mol/cm3；臭氧分压有类似的分布特征，极值146×10[-4]Pa，位于同一高度；(2) 在平流层低层，臭氧分压有一个次极值62×10[-4]Pa，位于15～16 km；(3) 0～30 km大气气溶胶数密度呈现出三个峰值:143，8和1.1 个/cm[3]，分别位于近地面、5 km和21 km；（4）气溶胶的数密度谱在对流层为双模态；在平流层，次峰消失。同时，我们还与其他观测结果作了比较分析。  相似文献   

Thermal diffusivity of lunar rocks under atmospheric and vacuum conditions     

Naoyuki Fujii  Masahiro Osako 《Earth and Planetary Science Letters》1973,18(1):65-71

Thermal diffusivity, k, of three lunar rocks (10049 and 10069; Type A, Apollo 11 and 14311; Apollo 14) and a terrestrial basalt (alkaline olivine basalt, Oki-do?go, Japan) was measured under one atmosphere and in vacuum conditions (10^?3 ～ 10^?5 mmHg) in the temperature range from 85 to 850°K. The semi-empirical curve of k =A + B/T +CT³ is fitted to the data in each condition. The porosity of rocks strongly affects the thermal diffusivity at low temperature ( T ? 500°K) in vacuum condition. At 150°K, thermal diffusivity of lunar rocks with porosity of 5.5% (10049) and 11% (10069) at one atmosphere is about 1.7 and 3.2 times of that in vacuum, respectively. The difference between the values at one atmosphere and those in vacuum decreases as the temperature increases. Measurements of k should be made at gas pressures at least lower than 10^?3 mmHg to estimate the value under lunar surface conditions.  相似文献   

On-going orogeny in the outer-arc of the Timor–Tanimbar region, eastern Indonesia     

Yoshiyuki Kaneko  Shigenori Maruyama  Ade Kadarusman  Tsutomu Ota  Masahiro Ishikawa  Tatsuki Tsujimori  Akira Ishikawa  Kazuaki Okamoto   《Gondwana Research》2007,11(1-2):218

The Timor–Tanimbar islands of eastern Indonesia form a non-volcanic arc in front of a 7 km deep fore-arc basin that separates it from a volcanic inner arc. The Timor–Tanimbar Islands expose one of the youngest high P/T metamorphic belts in the world, providing us with an excellent opportunity to study the inception of orogenic processes, undisturbed by later tectonic events.Structural and petrological studies of the high P/T metamorphic belt show that both deformation and metamorphic grade increase towards the centre of the 1 km thick crystalline belt. Kinematic indicators exhibit top-to-the-north sense of shear along the subhorizontal upper boundaries and top-to-the-south sense in the bottom boundaries of the high P/T metamorphic belt. Overall configuration suggests that the high P/T metamorphic rocks extruded as a thin sheet into a space between overlying ophiolites and underlying continental shelf sediments. Petrological study further illustrates that the central crystalline unit underwent a Barrovian-type overprint of the original high P/T metamorphic assemblages during wedge extrusion, and the metamorphic grade ranged from pumpellyite-actinolite to upper amphibolite facies.Quaternary uplift, marked by elevation of recent reefs, was estimated to be about 1260 m in Timor in the west and decreases toward Tanimbar in the east. In contrast, radiometric ages for the high P/T metamorphic rocks suggest that the exhumation of the high P/T metamorphic belt started in western Timor in Late Miocene time and migrated toward the east. Thus, the tectonic evolution of this region is diachronous and youngs to the east. We conclude that the deep-seated high P/T metamorphic belt extrudes into shallow crustal levels as a first step, followed by doming at a later stage. The so-called ‘mountain building’ process is restricted to the second stage. We attribute this Quaternary rapid uplift to rebound of the subducting Australian continental crust beneath Timor after it achieved positive buoyancy, due to break-off of the oceanic slab fringing the continental crust. In contrast, Tanimbar in the east has not yet been affected by later doming. A wide spectrum of processes, starting from extrusion of the high P/T metamorphic rocks and ending with the later doming due to slab break-off, can be observed in the Timor–Tanimbar region.  相似文献   

Preparation of Two New GSJ Geochemical Reference Materials: Basalt JB-1b and Coal Fly Ash JCFA-1   总被引：1，自引：0，他引：1  

Shigeru Terashima  Masahiro Taniguchi  Masumi Mikoshiba  Noboru Imai 《Geostandards and Geoanalytical Research》1998,22(1):113-117

  相似文献   

The shape of the gravitational potential in cold dark matter haloes     

Eric Hayashi  Julio F. Navarro †  Volker Springel 《Monthly notices of the Royal Astronomical Society》2007,377(1):50-62

  相似文献   

Stability Dependence and Diurnal Change of Large-Scale Turbulence Structures in the Near-Neutral Atmospheric Boundary Layer Observed from a Meteorological Tower     

Mitsuaki Horiguchi  Taiichi Hayashi  Ahoro Adachi  Shigeru Onogi 《Boundary-Layer Meteorology》2014,151(2):221-237

Based on the analysis of observations from a 213-m tall meteorological tower at Tsukuba, Japan, we have investigated the favourable conditions for the predominant existence of large-scale turbulence structures in the near-neutral atmospheric boundary layer (ABL). From the wavelet variance spectrum for the streamwise velocity component ( $u$ ) measured by a sonic anemometer-thermometer at the highest level (200 m), large-scale structures (time-scale range of 100–300 s) predominantly exist under slightly unstable and close to neutral conditions. The emergence of large-scale structures also can be related to the diurnal evolution of the ABL. The large-scale structures play an important role in the overall flow structure of the lower boundary layer. For example, $u$ velocity components at the 200-m and 50-m levels show relatively high correlation with the existence of large-scale structures. Under slightly unstable (near-neutral) conditions, a low-speed region in advance of the high-speed structure shows a positive deviation of temperature and appears as the plume structure that is forced by buoyancy in the heated lower layer. In spite of the difference in buoyancy effects between the near-neutral and unstable cases, large-scale structures are frequently observed in both cases and the same vertical correlation of $u$ components is indicated. However, the vertical wind shear is smaller in the unstable cases. On the other hand, in near-neutral cases, the transport efficiency of momentum at the higher level and the flux contribution of sweep motions are larger than those in the unstable cases.  相似文献   

Permafrost‐thaw‐induced land‐cover change in the Canadian subarctic: implications for water resources     

W.L. Quinton  M. Hayashi  L.E. Chasmer 《水文研究》2011,25(1):152-158

Climate warming and human disturbance in north‐western Canada have been accompanied by degradation of permafrost, which introduces considerable uncertainty to the future availability of northern freshwater resources. This study demonstrates the rate and spatial pattern of permafrost loss in a region that typifies the southern boundary of permafrost. Remote‐sensing analysis of a 1·0 km² area indicates that permafrost occupied 0·70 km² in 1947 and decreased with time to 0·43 km² by 2008. Ground‐based measurements demonstrate the importance of horizontal heat flows in thawing discontinuous permafrost, and show that such thaw produces dramatic land‐cover changes that can alter basin runoff production in this region. A major challenge to northern water resources management in the twenty‐first century therefore lies in predicting stream flows dynamically in the context of widely occurring permafrost thaw. The need for appropriate water resource planning, mitigation, and adaptation strategies is explained. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Relations between load and settlement of circular foundations on or in a dense sand expressed by a function of diameter and depth     

Hiroaki Nagaoka  Masahiro Yamazaki  Naoto Kubota  Takashi Okamoto 《国际地质力学数值与分析法杂志》2005,29(6):551-576

When load acts on a circular foundation on or in a dense sand, average contact pressure on the lower surface of the foundation is q and settlement of the foundation is s. Diameter and depth of the foundation are B and D_f. When the sand, B and D_f are given, we can know the relation between q and s/B by, e.g. a loading test, i.e. the relation is determined by B and D_f for the sand. Using the results of numerical analyses, we express a relation between q and s/B up to s=0.1B by functions of a single variable which is a linear combination of B and D_f. Consequently when two foundations have different B's and different D_f's but have the same value of the variable, the relations are the same. Then we examine whether the functions can express the results of eleven tests of model foundations of wide range of B and/or D_f. In all the tests, the relations are expressed with sufficient accuracy. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Standardization of baseline and additionality determination under the CDM     

Daisuke Hayashi  Axel Michaelowa 《Climate Policy》2013,13(2):191-209

Clean Development Mechanism (CDM) project developers have long complained about the complexities of project-specific baseline setting and the vagaries of additionality determination. In response to this, the CDM Executive Board took bold steps towards the standardization of CDM methodologies, culminating in the approval of guidelines for the establishment of performance standards in November 2011. The guidelines specify a performance standard stringency level for both baseline and additionality of 80% for several priority sectors and 90% for all other sectors. However, an analysis of 14 large-scale CDM methodologies that use performance standard approaches challenges this top-down approach to the performance standard design. An appropriate performance standard stringency level strongly depends on sector and technology characteristics. A single stringency level for baseline and additionality determination is appropriate only for greenfield projects, but not for retrofit ones. Overly simple, highly aggregated performance standards are unlikely to ensure high environmental integrity, and difficult questions regarding stringency and updating frequency will eventually have to be addressed on a rather disaggregated level. A careful balance between data requirements and the practicability of performance standards is essential because the heavy data requirements of the existing performance standard methodologies have been the key barrier to their actual implementation.

Policy relevance

CDM regulators have been pushed by many stakeholders to standardize baseline setting and eliminate project-specific additionality determination. At first glance, performance standards seem to provide the perfect solution for both tasks. However, a one-size-fits-all political decision – e.g. the average of the top 20% performers as enshrined in the Marrakech Accords – is inappropriate. Substantial disaggregation of performance standards is required both technologically and geographically in order to limit over- and under-crediting and close loopholes for non-additional projects. As a lack of reliable and complete data has been and will be a key bottleneck for the development of performance standards, international support for data collection will be indispensable, but costly, and time-consuming. Empirically driven, techno-economic assessments of performance standard stringency levels must be the central task of the future work on standardized methodologies, and should not be sidelined by perceived needs of policy makers to take bold decisions under time pressures.  相似文献   

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance     

J. Todd Hoeksema  Yang Liu  Keiji Hayashi  Xudong Sun  Jesper Schou  Sebastien Couvidat  Aimee Norton  Monica Bobra  Rebecca Centeno  K. D. Leka  Graham Barnes  Michael Turmon 《Solar physics》2014,289(9):3483-3530

The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable quantities, including the photospheric vector magnetic field, from sequences of filtergrams. The basic vector-field frame list cadence is 135 seconds, but to reduce noise the filtergrams are combined to derive data products every 720 seconds. The primary 720 s observables were released in mid-2010, including Stokes polarization parameters measured at six wavelengths, as well as intensity, Doppler velocity, and the line-of-sight magnetic field. More advanced products, including the full vector magnetic field, are now available. Automatically identified HMI Active Region Patches (HARPs) track the location and shape of magnetic regions throughout their lifetime. The vector field is computed using the Very Fast Inversion of the Stokes Vector (VFISV) code optimized for the HMI pipeline; the remaining 180^° azimuth ambiguity is resolved with the Minimum Energy (ME0) code. The Milne–Eddington inversion is performed on all full-disk HMI observations. The disambiguation, until recently run only on HARP regions, is now implemented for the full disk. Vector and scalar quantities in the patches are used to derive active region indices potentially useful for forecasting; the data maps and indices are collected in the SHARP data series, hmi.sharp_720s. Definitive SHARP processing is completed only after the region rotates off the visible disk; quick-look products are produced in near real time. Patches are provided in both CCD and heliographic coordinates. HMI provides continuous coverage of the vector field, but has modest spatial, spectral, and temporal resolution. Coupled with limitations of the analysis and interpretation techniques, effects of the orbital velocity, and instrument performance, the resulting measurements have a certain dynamic range and sensitivity and are subject to systematic errors and uncertainties that are characterized in this report.  相似文献