Interpretation of Mauna Loa atmospheric transmission relative to aerosols,using photometric precipitable water amouts     

Ellsworth G. Dutton  John J. Deluisi  P. Arne 《Journal of Atmospheric Chemistry》1985,3(1):53-68

Precipitable water measurements made coincident in time and space with direct broadband solar irradiance measurements are used in conjunction with an atmospheric transmission model to derive a parameter whose major dependence is on total aerosol extinction. Irradiance measurements are used to calculate an atmospheric transmission factor (ATF) that is independent of the instrument calibration and the extraterrestrial solar constant. The dependency of the ATF on precipitable water is determined using LOWTRAN5, an atmospheric transmission model with high spectral resolution. Precipitable water measurements are then used to adjust the measured ATF to correspond to an ATF value obtained for a constant precipitable water amount. The remaining variability in the adjusted ATF is due mostly to aerosol extinction. The technique is applied to a 6-year period (1978–1983) for clear-sky mornings at Mauna Loa, Hawaii (MLO). MLO ATF aerosol residuals are compared with independently measured monochromatic aerosol optical depth. Results show that the ATF aerosol residual is nearly equal to the 500 nm aerosol optical depth prior to the eruption of E1 Chichon, at which time a nonlinear time-dependent relationship between the two quantities is evident. ATF aerosol residuals reflect the spectrally integrated aerosol influence on transmission and, therefore, could indicate better than monochromatic optical depth the radiation balance perturbations due to aerosols. The 6-year precipitable water record for MLO, determined from a dual-channel sunphotometer, has a mean value of 0.3 cm. An annual cycle in precipitable water is evident, as is a 4-month 5-standard-deviation drought from December 1982 through March 1983.  相似文献   

Transport of water in frozen soil: V, Method for measuring the vapor diffusivity when ice is absent     

Yoshisuke Nakano  Allen R. Tice  Thomas F. Jenkins 《Advances in water resources》1984,7(4):172-179

A new experimental method is introduced for determining the relative magnitudes of liquid and vapor diffusion by using a small amount of soluble chemical as a tracer. The theoretical justification of the method is presented for the case where ice is absent. The feasibility of the method is demonstrated by an experiment using marine-deposited clay.  相似文献   

不同雨强台风的诊断对比与数值试验研究   总被引：13，自引：2，他引：13  

丁治英  陈久康 《南京气象学院学报》1995,18(2):234-241

通过对不同雨强台风的诊断对比及数值试验得出一些结论。台风暴雨与锋区、高低空急流有关。强锋区可导致２００ｈｐａ西南风高空急流与右后房非地转辐散的加强，并在其作用下，激发重力惯性波。其调整过程，即为暴雨的突然增幅过程。调整时间约３￣６小时。调整过程使低空急流加强，加大向暴雨区的水汽动量输送，有利于降水加强。调整过程结束后，雨量变化平稳。  相似文献   

黄土高原上两次低空东北急流大暴雨的诊断分析   总被引：8，自引：5，他引：8  

刘子臣  张健宏 《高原气象》1995,14(1):107-113

通过对黄土高原上两次没有低空西南急流参与的区域性大暴雨的分析，发现低空东北急流在两次暴雨中份演了主要角色，因此，称这类暴雨为东北急流暴雨，与西南急流对比分析后认为，两种急流有很大同，东北急流具有自己的特点。文章最后给出了东北急流暴雨的三股气流模式。  相似文献   

浅埋软弱地层隧道旋喷预衬砌支护技术的研究   总被引：3，自引：0，他引：3       下载免费PDF全文

李远宁  段玉刚吴胜 《探矿工程》2001,(5):58-61

论述了浅埋软弱地层隧道旋喷预衬砌支护的研究背景及国内外研究现状、室内试验、旋喷器具、施工工艺及应用情况,并与其它施工方法进行了对比,效益显著。  相似文献   

Hydrodynamical Modeling Of Oceanic Vortices   总被引：1，自引：0，他引：1  

Xavier Carton 《Surveys in Geophysics》2001,22(3):179-263

Mesoscale coherent vortices are numerous in the ocean.Though they possess various structures in temperature and salinity,they are all long-lived, fairly intense and mostly circular. Thephysical variable which best describes the rotation and the density anomaly associated with coherent vortices is potential vorticity. It is diagnostically related to velocity and pressure, when the vortex is stationary. Stationary vortices can be monopolar (circular or elliptical) or multipolar; their stability analysis shows thattransitions between the various stationary shapes are possible when they become unstable. But stable vortices can also undergo unsteady evolutions when perturbed by environmental effects, likelarge-scale shear or strain fields, -effect or topography. Changes in vortex shapes can also result from vortex interactions. such as the pairing, merger or vertical alignment of two vortices, which depend on their relative polarities and depths. Such interactions transfer energy and enstrophy between scales, and are essential in two-dimensional and in geostrophic turbulence. Finally, in relation with the observations, we describe a few mechanisms of vortex generation.  相似文献   

山东省飞机增雨天气系统云水资源转化特征分析   总被引：5，自引：1，他引：5  

龚佃利  边道相 《气象》2002,28(8):15-19

利用水汽辐合法和水汽凝结法，对山东省1997－1999年春秋季18个降水过程的水汽辐合率、凝结率及降水效率等表征云水资源及其转化的特征量进行计算。分析了南方气旋、西北冷锋等主要降水天气系统以上特征量的地域分布和差别。可为人工增雨作业区域选择和航线设计提供气候背景。  相似文献   

利用GPS技术遥感大气对流层水汽含量的研究   总被引：2，自引：0，他引：2  

丁继新  成英燕  王权  党亚民 《测绘科学》2002,27(2):16-19

讨论了利用 GPS系统探测大气对流层水汽含量的原理和数学模型 ,对利用 GPS遥感大气对流层水汽的加权平均温度、水汽含量随时间的变化等一些关键问题进行了探讨。通过对我国沿海地区大连、青岛、闸坡、坎门、厦门 5个测站的实验数据的解算 ,获得了较为满意的结果。  相似文献   

用地面湿度参量计算我国整层大气可降水量及有效水汽含量方法的研究   总被引：56，自引：3，他引：56       下载免费PDF全文

杨景梅  邱金桓 《大气科学》2002,26(1):9-22

根据1993年我国28个台站地面及高空气象要素资料,拟合出这28个台站所在地区整层大气可降水量同地面湿度参量(地面水汽压、地面露点)关系的经验表达式,并且在此基础上,通过引进地理纬度ψ和海拔高度H两个参量,将经验系数参数化,建立起由地面湿度参量计算整层大气可降水量的经验计算模式.另外还拟合出这些地区整层大气有效水汽含量同可降水量关系的经验表达式,提出一个先由地面湿度参量计算整层大气可降水量,再由此计算出整层大气有效水汽含量的方法.  相似文献   

大气环流的变化与南海夏季风活动的关系   总被引：1，自引：0，他引：1  

陈双溪  何财福 《气象》2002,28(5):11-16

通过对近20年观测资料的计算分析表明，在南海夏季风活跃与中断期，南北半球副热带西风急流和热带东风急流以及青藏高压和墨西哥高压有明显的差异。从南半球向北传播的散度场低频振荡以及从北半球高纬向南传播的西风场低频振荡等的有利位相同时传入南海并共同作用可引起南海夏季风的活跃或中断。各种低频振荡的有利位相传播到南海并发生锁相的时间决定着南海夏季风明显的活跃或中断发生的时间。  相似文献