An advanced irradiation facilities and its usage

1 INTRODUCTION Carrier type gamma irradiation, a new tech- nology have been developed rapidly in recent dec- ades in industry, agriculture, and science and tech- nology. In Qingdao Irradiation Center (QIC), a car- rier-type irradiator in overlapping sourc…     

30-60-day Oscillations of Convection and Circulation Associated with the Thermal State of the Western Pacific Warm Pool during Boreal Summer

This study focuses on the characteristics of the 30-60-day oscillation (MJO) associated with the interannual variability of the thermal state in the western Pacific warm pool. The composite results show that the amplitude of MJO convection over the tropical western Pacific tends to intensify (reduce) in the WARM (COLD) case. The negative correlations between MJO convection in the WARM and inthe COLD cases are examined to be significant over most of the Asian-Pacific region. The evolutions of MJO convection and lower circulation, on the one hand, exhibit larger differences between the WARM and COLD cases, but on the other hand, display a unique feature in that a well-developed MJO cyclone (anticyclone) is anchored over the Asian-Western Pacific domain at the peak enhanced (suppressed) MJO convection phase over the western Pacific warm pool, either in the WARM or in the COLD case. This unique feature of MJO shows a Gill-type response of lower circulation to the convection and is inferred to be an inherent appearance of MJO. The context in the paper suggests there may exist interactions between MJO and the interannual variability of the thermal state in the western Pacific warm pool.     

Nonseparable stationary anisotropic space–time covariance functions

Obtaining new and flexible classes of nonseparable spatio-temporal covariances and variograms has resulted a key point of research in the last years. The goal of this paper is to introduce and develop new spatio-temporal covariance models taking into account the problem of spatial anisotropy. Recent literature has focused on the problem of full symmetry and the problem of anisotropy has been overcome. Here we propose a generalization of Gneiting’s (J Am Stat Assoc 97:590–600, 2002a) approach and obtain new classes of stationary nonseparable spatio-temporal covariance functions which are spatially anisotropic. The resulting structures are proved to have certain interesting mathematical properties, together with a considerable applicability.Work partially funded by grant MTM2004-06231 from the Spanish Ministry of Science and Education.     

不忘初心,砥砺奋进,为新时代国家生态安全和东北区域农业发展贡献科技力量——中国科学院东北地理与农业生态研究所建所60周年回顾

中国科学院东北地理与农业生态研究所（简称东北地理所）是中国科学院设立在东北地区的综合性地理科学、农业科学和环境科学研究机构和人才培养基地。2018年,东北地理所迎来了60周岁的生日。60 a来,东北地理所不断凝练科学目标,调整和完善学科布局与科研组织结构,推动了相关学科发展;强化人才引进和自主培养相结合,人才队伍结构和创新能力得到极大加强;瞄准世界科学前沿,取得了一批独具特色的重大基础研究成果,一大批有重要影响的技术成果取得突破并应用于国家生态建设与东北区域农业发展;发展和完善了绩效考评体系、成果转移转化机制和协同创新机制,和谐奋进的创新文化环境正在形成。     

ANALYSIS ON THE SOURCE AND SINK OF KINETIC ENERGY OF ATMOSPHERIC 30-60 DAY PERIOD OSCILLATION AND THE PROBABLE CAUSES*

Based on ECMWF daily grid point data in summer(May-August),1981,the distribution features of the source and sink of kinetic energy of atmosphere 30-60 day oscillation,including its horizontal distribution characteristics and its vertical structure characteristics,are investigated systematically with diagnostic analysis methods over a latitude belt between 80°N and 60°S.Also,the probable reasons for the existence of the source and sink of low frequency kinetic energy(LFKE) are discussed preliminarily.Results show that the horizontal distribution of the sources and sinks of kinetic energy of atmospheric 30-60 day oscillation is extremely different.The significant sources and sinks of LFKE mainly exist in the oceans and the coastal regions of continents or islands in the mid-high latitudes.It is also found that,in the vertical direction,the sources and sinks of kinetic energy of 30-60 day oscillation display barotropic structure in the mid-high latitudes of both hemispheres,but dispaly baroclinic structure in the equtorial region,and in the horizontal direction,the sources and sinks mainly display zonal wave-like distribution.The source and sink of LFKE are determinded by ageostrophic wind effect,frictional effect,interaction between sub-grid-scale systems,nonlinear interaction,and the flux-divergence of LFKE transported by transient wind.There are some regional reasons for the generation of sources and sinks which are not completely identical in different areas.     

CISK-rossby wave and the 30-60 Day Oscillation in the Tropics

The 30-60 day oscillation is an important aspect of the atmospheric variance in the tropical area. A number of works have been done on this phenomenon, this article is a further one. A quasi-geostrophic linear model that consists of a two-layer free atmosphere and a well-mixed boundary layer is used to investigate the instability of intraseasonal oscillation, its propagation and vertical structures. Results show that the dynamical coupling and interaction between the barotropic and baroclinic components via boundary layer convergence / divergence are responsible for the appearance of a new kind of low-frequency wave. Such wave is very different from the traditional tropical Rossby wave. It can propagate westward and eastward. Some behaviours of it appear to resemble the observed 30-60 day oscillation mode in many aspects, such,as vertical structures, zonal and meridional propagations. Now many researchers emphasize the direct relationship between CISK-Kelvin mode and the tropical atmospheric 30-60 oscil     

Vertical structure and characteristics of 23–60 day (zonal) oscillations over the tropical latitudes during the winter months of 1986 — Results of equatorial wave campaign—II

The equatorial wave campaign-II which formed a part of the Indian Middle Atmosphere Programme (IMAP), was conducted from SHAR (13.7°N, 80.2°E) from 15 January to 28 February 1986. Winds were measured from ground to 60 km by means of high altitude balloon and a meteorological rocket (RH-200), once everyday, for 45 days. The frequencies of the oscillations in the deviations of the east-west component of the winds from its mean at each height with one kilometer interval were obtained by the maximum entropy (ME) method and phases/amplitudes of these frequencies were determined by the least squares technique on the wind variation time series. The ME method has the inherent advantage of providing periodicities up to 1.5 times the data length. The height structure of the long period waves of > 23 day periodicities that have larger amplitudes nearly by a factor of 2 as compared to the medium (9 to 22 day) or shorter period (4 to 8 day) ones, reveal two height regions of enhanced amplitudes, one in the troposphere and another in the upper stratosphere/lower mesosphere, that too, mostly in the regions of positive (westerly increasing or easterly decreasing with height) wind shears. The waves are seen to be inhibited in the negative wind shear regions. From the abrupt changes in the altitude variation of phase, the possible source region has been identified. The vertical wavelengths have been estimated to be 34 km and 19 km in the troposphere and lower stratosphere respectively and 8 km in the upper stratosphere and lower mesosphere. Around 56 km the wave amplitude is reduced to 1/4 of its value below, while the vertical shear strength in the mean wind doubled up. The tropospheric waves are suggested to be Rossby waves of extratropical origin penetrating to tropical latitudes. The stratospheric/mesospheric waves however appear to emanate from a source around the stratopause.     

风廓线雷达反演温度平流的应用

利用北京延庆站风廓线雷达水平风廓线资料进行大气温度平流的反演,详细分析2014年11月15日夜间冷空气入侵过程,并统计分析2015年9—11月6次冷空气入侵过程,同T639L60模式的预报风场及温度平流预报产品进行对比。结果表明:在一定预报时效内 (约6~12 h),风廓线雷达获取的水平风廓线与模式给出的预报风场有较好的一致性;由风廓线雷达反演的温度平流与模式给出的温度平流量级相同,温度平流属性一致;风廓线雷达6 min完成1次垂直高度分辨率为120 m的探测,高时空分辨率使风廓线雷达获取的温度平流较T639L60模式更能反映大气温度平流的细节。     

Laboratory Kinetic Studies of the Reactions of Cl Atoms with Species of Biogenic Origin: δ3-Carene, Isoprene, Methacrolein and Methyl Vinyl Ketone

The rate coefficients for the reaction between atomic chlorine and a number of naturally occurring species have been measured at ambient temperature and atmospheric pressure using the relative rate technique. The values obtained were (4.0 ± 0.8) × 10^-10, (2.1 ± 0.5) × 10^-10, (3.2 ± 0.5) × 10^-10, and (4.9 ± 0.5) × 10^-10 cm³ molecule^-1 s^-1, for reactions with isoprene, methyl vinyl ketone, methacrolein and 60/xxlarge948.gif" alt="delta" align="BASELINE" BORDER="0">³-carene, respectively. The value obtained for isoprene compares favourably with previously reported values. No values have been reported to date for the rate constants of the other reactions.     

中国历史山洪灾害分布特征研究

中国山洪灾害发生频繁,区域分布差异性明显且难以预报,关于山洪灾害分布特征的研究对于山洪灾害预警、山洪灾害防治区规划等具有重要意义。本文以历史山洪灾害点为基础数据,以6个一级地貌大区（东部平原低山丘陵大区（Ⅰ）、东南低山丘陵平原大区（Ⅱ）、华北-内蒙东中山高原大区（Ⅲ）、西北高中山盆地高原大区（Ⅳ）、西南中低山高原盆地大区（Ⅴ）、青藏高原高山极高山盆地谷地大区（Ⅵ））为基本分析单元,统计对比不同地貌区域内山洪灾害数目、密度,并进一步分析山洪灾害随高程、高程标准差以及50年一遇6 h雨量（H6-50）的分布情况,从而获得中国历史山洪灾害的主要分布特征。结果表明：山洪灾害集中分布于东南低山丘陵平原大区及西南中低山高原盆地大区,占全国山洪灾害的60%左右。6 h雨量（H6-50）处于240~280 mm区域山洪灾害密度最大。高程标准差小于30 m区域山洪灾害密度较大。东南低山丘陵平原大区高程处于10~50 m间,高程标准差小于30 m,雨量（H6-50）在150~270 mm间地区山洪灾害密度较大;西南中低山高原盆地大区山洪灾害集中分布于高程600 m以下,高程标准差小于50 m,雨量（H6-50）大于120 mm地区。以地貌区划结果为基本分析单元相对于行政界线而言更有助于分析山洪灾害分布特征。