我涂日照纸

日照纸涂药质量的好坏,直接关系到日照纸的感光及今后的保存。如果日照纸表面油脂没有擦净,或者即使油脂擦净,涂药时没有让日照纸“吃药”到一定的程度。都会使日照纸上的感光迹线消退。为使涂药达到要求,我是这样做的:     

也谈日照纸的涂药

日照纸的涂药质量,直接关系到日照记录的准确性。目前多数台站采用效果比较理想的混合涂药法。但采用这种方法,必须注意几点,方能保证质量。现将我站的方法介绍如下: 1.按规范规定,涂药前,必须先用脱脂棉把需涂药的日照纸表面逐张擦净。在擦纸时,用力要轻而均匀,按纸上的竖行由上往下擦,不宜过份用力,以免把日照纸擦起毛。否则,涂药时,药水既易渗透纸背,使感光迹线模糊,也不利于日照纸的长久保存。 2.配药时使用蒸馏水并按规定配量。因     

新日照纸涂药之我见

20 0 0年 4月出厂的新日照纸比 1 991年 7月出厂的旧日照纸光滑、洁白 ,但用同样的药、同样的比例仍采用两步涂药法 ,却不能获得理想的日照记录。经多次试验发现 ,新日照纸采用一步涂药法 (混合涂药法 )比较合适 ,但浓度偏大。我局经过试验 ,采用的比例是 :赤血盐∶枸缘酸铁铵∶水 =1∶4∶8,浸泡后日照纸呈现淡蓝色且异常清晰。新日照纸涂药之我见@李倩倩$孟津县气象局!河南孟津471100     

介绍日照纸的另一种涂药方法

《地面气象观测规范》介绍了两种日照纸的涂药方法,但据了解,用该两种方法涂刷的日照纸,效果总是欠佳。作者从实际工作中摸索到另一种涂药方法,现简介如下。１ 涂液的配制 赤血盐２ｇ,柠檬酸铁铵２ｇ,混合于一开口的容器里,加水５０ｇ,充分搅拌至药品全部溶解。把配制好的药液盛入棕色避光的瓶里（瓶体需用黑纸包裹）,加盖避光存放。２ 涂药的要求 涂刷日照纸应在暗处或夜间弱光（最好是红光）灯下进行。涂药前,必须先用脱脂棉把需要涂药的日照纸表面擦净,另用毛笔沾上药液涂在日照纸上,涂药要薄而均匀。涂好后的日照纸,在暗处…     

日照纸能否感光的检验方法

地面气象观测工作中 ,日照纸涂药有两种方法 :混合涂药法和两步涂药法。由于混合涂药法比较方便 ,因此使用普遍。《地面气象观测规范》规定 ,混合涂药法是将按比例配制好的赤血盐和枸橼酸铁铵溶液等量混合搅匀 ,再涂刷日照纸。涂刷的环境是在暗处或弱的光线下 ,因此日照纸感光效果有必要进行检验。在工作中 ,我们使用台灯进行感光效果检验。方法是 :取一张日照纸放在台灯下 (最好是日光式的台灯 )照 3～ 5分钟 ,看日照纸颜色是否变蓝。感光好的日照纸变蓝快 ,否则变蓝慢 ,没有感光的不变色。感光不好说明药品比例配制不当 ,没有感光的是药品…     

提高暗筒式日照纸感光质量的技巧

暗筒式日照计日照纸所用药品品质好坏、配药比例和涂药方法是否得当,是造成日照纸感光质量好坏的主要原因。本文针对部分测报员在日照纸配药、涂药和浸漂操作处理过程中存在的问题提出相关改进措施和建议。     

地面观测经验二则

1 日照纸涂药办法经验谈 目前上级配置的涂日照纸用的药品,一改过去的瓶装为简易包装,造成药品质量极不稳定。若按《规范》提供的办法进行涂药,日照纸涂药后的纸底色肯定偏蓝,且易变深蓝色,易与日照迹线相混,甚至影响测报质量。对此,本人经多次反复实践,认为在涂药当中,若做到如下几点,结果将会有所改观: 1) 涂药之前一定要用脱脂棉去掉表面油脂,但擦纸时不可太用力,用力要均匀。 2) 药液的配制:两种药以1:1比例为宜。两种药与水之比例以1:15为宜,药液一定要静置5分钟左右才可涂刷。 3) 涂药时先另用脱脂棉蘸满药水,然后轻轻地横向涂满整张纸,再挤干棉花药水后,纵向吸干药水。这种涂药方法将会自然“薄而均匀”。     

用烘干法涂日照纸

在测报工作中,日照纸涂药是一项较烦的工作。按规范规定,每次涂药前要用脱脂棉把自记纸擦一遍,以去掉表面油脂。均匀涂药后阴干备用,规定每次涂药不宜超过10张。经本人多年实践和对比,觉得用烘干法处理涂药较规范规定之方法有较大的长处。 1 问题的提出 在日常业务工作中发现,用同样的药水所涂的日照纸放在同样的地方,在气候干燥的日子里,其存放时间可长些;在潮湿的日子里,四天左右就要变质。显而易见,这二种日照纸经日射感光后的结果是不同的。前者底色清白或略带淡蓝色,而后者则呈一片蓝色。由此使我联想到涂好药的日照纸的储存与湿度关系甚大。只要相对减少储存环境的湿度,就有可能较好地保持日照纸的新鲜程度。密封除湿是不切合实际的,但采用烘干法则是有可能的。在这种想法驱使下,我采用电热台板烘干涂日照纸,取得较好的效果。     

日照纸涂药体会点滴

日照纸感光不良在我们这里常发生,大家知道:日照纸上的感光迹线是否正常,与配药、涂药、药品质量有很大关系。近年来下发给台站的柠檬酸铁铵质量较差,普遍反映感光不好,如果不注意配药和涂药工艺,更会容易出现感光不良现象。 我们站用的是两步涂药法,同样的药品,同样按规范规定的配方和方法,工艺上不过细得出的结果就不一样。例如,有的同志涂的日照纸看起来均匀、整洁,感光迹线清晰,洗后纸的颜色呈白色;而有的同志涂的日照纸看起来颜色深浅不均,迹线难以辨别,洗后纸呈蓝色、黄色或蓝黄混合色。问题出在哪里呢?经我们多次分析认为:主要是涂药时药水浸进了纸内,故造成感光不良     

日照纸涂药及使用中的几个问题及处理方法

通过分析日照纸的几种异常情况及出现原因,对日照纸的药液配置、涂药、浸泡、保存等做了详细介绍,对提高日照记录质量会有较大帮助.     

Summer dryness in a warmer climate: a process study with a regional climate model

Earlier GCM studies have expressed the concern that an enhancement of greenhouse warming might increase the occurrence of summer droughts in mid-latitudes, especially in southern Europe and central North America. This could represent a severe threat for agriculture in the regions concerned, where summer is the main growing season. These predictions must however be considered as uncertain, since most studies featuring enhanced summer dryness in mid-latitudes use very simple representations of the land-surface processes ("bucket" models), despite their key importance for the issue considered. The current study uses a regional climate model including a land-surface scheme of intermediate complexity to investigate the sensitivity of the summer climate to enhanced greenhouse warming over the American Midwest. A surrogate climate change scenario is used for the simulation of a warmer climate. The control runs are driven at the lateral boundaries and the sea surface by reanalysis data and observations, respectively. The warmer climate experiments are forced by a modified set of initial and lateral boundary conditions. The modifications consist of a uniform 3 K temperature increase and an attendant increase of specific humidity (unchanged relative humidity). This strategy maintains a similar dynamical forcing in the warmer climate experiments, thus allowing to investigate thermodynamical impacts of climate change in comparative isolation. The atmospheric CO ₂ concentration of the sensitivity experiments is set to four times its pre-industrial value. The simulations are conducted from March 15 to October 1st, for 4 years corresponding to drought (1988), normal (1986, 1990) and flood (1993) conditions. The numerical experiments do not present any great enhancement of summer drying under warmer climatic conditions. First, the overall changes in the hydrological cycle (especially evapotranspiration) are of small magnitude despite the strong forcing applied. Second, precipitation increases in spring lead to higher soil water recharge during this season, compensating for the enhanced soil moisture depletion occurring later in the year. Additional simulations replacing the plant control on transpiration with a bucket-type formulation presented increased soil drying in 1988, the drought year. This suggests that vegetation control on transpiration might play an important part in counteracting an enhancement of summer drying when soil water gets limited. Though further aspects of this issue would need investigating, our results underline the importance of land-surface processes in climate integrations and suggest that the risk of enhanced summer dryness in the region studied might be less acute than previously assumed, provided the North American general circulation does not change markedly with global warming.     

Continental vegetation as a dynamic component of a global climate model: a preliminary assessment

A simplified vegetation distribution prediction scheme is used in combination with the Biosphere-Atmosphere Transfer Scheme (BATS) and coupled to a version of the NCAR Community Climate Model (CCM1) which includes a mixed-layer ocean. Employed in an off-line mode as a diagnostic tool, the scheme predicts a slightly darker and slightly rougher continental surface than when BATS' prescribed vegetation classes are used. The impact of tropical deforestation on regional climates, and hence on diagnosed vegetation, differs between South America and S.E. Asia. In the Amazon, the climatic effects of removing all the tropical forest are so marked that in only one of the 18 deforested grid elements could the new climate sustain tropical forest vegetation whereas in S.E. Asia in seven of the 9 deforested elements the climate could continue to support tropical forest. Following these off-line tests, the simple vegetation scheme has been coupled to the GCM as an interactive (or two-way) submodel for a test integration lasting 5.6 yr. It is found to be a stable component of the global climate system, producing only ~ 3% (absolute) interannual changes in the predicted percentages of continental vegetation, together with globally-averaged continental temperature increases of up to + 1.5 °C and evaporation increases of 0 to 5 W m^–2 and no discernible trends over the 67 months of integration. On the other hand, this interactive land biosphere causes regional-scale temperature differences of ± 10 °C and commensurate disturbances in other climatic parameters. Tuning, similar to the q-flux schemes used for ocean models, could improve the simulation of the present-day surface climate but, in the longer term, it will be important to focus on predicting the characteristics of the continental surface rather than simple vegetation classes. The coupling scheme will also have to allow for vegetation responses occurring over longer timescales so that the coupled system is buffered from sudden shocks.     

Numerical analysis of a thermotopographically-induced mesoscale circulation in a mountain basin using a non-hydrostatic model

Summary The boundary-layer wind field during weak synoptic conditions is largely controlled by the nature of the landscape. Mesoscale (sub-synoptic) circulations result from horizontal gradients of sensible heat flux due to variation in local topography, variation in surface-cover, and discontinuities such as land-sea contrasts. Such flows are usually referred to as thermally-driven circulations, and are diurnal in nature and often predictable. In this paper we use a state-of-the-art non-hydrostatic computer model to shed light on the physical mechanisms that drive a persistent easterly wind that develops in the afternoon in the Mackenzie Basin, New Zealand. The easterly – Canterbury Plains Breeze (CPB) – is observed early in the afternoon and is often intense, with mean wind speeds reaching up to 12 m s⁻¹. Although computer modelling in mountainous terrain is extremely challenging, the model is able to simulate this circulation satisfactorily. To further investigate the mechanisms that generate the Canterbury Plains Breeze, two additional idealized model experiments are performed. With each experiment, the effects of the synoptic scale wind and the ocean around the South Island, New Zealand were successively removed. The results show that contrary to previous suggestions, the Canterbury Plains Breeze is not an intrusion of the coastal sea breeze or the Canterbury north-easterly, but can be generated by heating of the basin alone. This conclusion highlights the importance of mountain basins and saddles in controlling near-surface wind regimes in complex terrain.     

A cold air lake formation in a basin — a simulation with a mesoscale numerical model

Summary A formation of a cold air lake in a basin is studied with a mesometeorological model.A dynamic Boussinesq hydrostatic mesoscale numerical model is developed in a staggered orthogonal grid with a horizontal resolution of 1 km and with a varying vertical grid. The topography is presented in a block shape so that computation levels are horizontal.The mesometeorological model is tested in three idealized topography cases (a valley, a single mountain, a basin) and test results are discussed.In an alpine basin surrounded by mountains and plateaus the air is supposed to be stagnant at the beginning of the night. Due to differences in radiation cooling an inversion layer is formed in the basin and local wind circulation is studied by model simulations.With 14 Figures     

Effects of a Fence on Pollutant Dispersion in a Boundary Layer Exposed to a Rural-to-Urban Transition

Simultaneous particle-image velocimetry and laser-induced fluorescence combined with large-eddy simulations are used to investigate the flow and pollutant dispersion behaviour in a rural-to-urban roughness transition. The urban roughness is characterized by an array of cubical obstacles in an aligned arrangement. A plane fence is added one obstacle height h upstream of the urban roughness elements, with three different fence heights considered. A smooth-wall turbulent boundary layer with a depth of 10h is used as the approaching flow, and a passive tracer is released from a uniform line source 1h upstream of the fence. A shear layer is formed at the top of the fence, which increases in strength for the higher fence cases, resulting in a deeper internal boundary layer (IBL). It is found that the mean flow for the rural-to-urban transition can be described by means of a mixing-length model provided that the transitional effects are accounted for. The mixing-length formulation for sparse urban canopies, as found in the literature, is extended to take into account the blockage effect in dense canopies. Additionally, the average mean concentration field is found to scale with the IBL depth and the bulk velocity in the IBL.     

Evaporation from a blanket bog in a foggy coastal environment

Frequent fog severely restricts evaporation from blanket bogs in Newfoundland because it more than halves the radiant energy input, and it eliminates the vapor pressure deficit, resulting in evaporation at the equilibrium rate (average = 0.99 during fog). During these periods, there is no surface resistance to evaporation because the bog has been wetted by fog drip, and although the latent heat flux dominates over sensible heat (average = 0.8), both are small. In contrast, the surface dries during clear periods, increasing the surface resistance to evaporation so that sensible heat becomes more important ( = 1.05). When the mosses are dry, evaporation is below the equilibrium rate ( = 0.87), although the higher available energy ensures that actual evaporation is higher. During clear periods, daily evaporation averaged 2.5 mm, compared to 1.1 and 0.7 mm for fog and rain, respectively. The suppressed evaporation at this site is important in maintaining appropriate hydrological conditions for blanket bog development.     

Parameterization of a momentum source in a tropical cumulus ensemble

Summary An eddy effect of tropical deep convection on the large-scale momentum, resp vorticity budget is investigated. The process is specified by a simple parameterization approach which is based on a concept of rotating clouds exerting a momentum on the large-scale flow. The cloud rotation is associated with the thermal properties of a cloud ensemble by the principle of conservation of potential vorticity. A decomposition of cloud classes is applied in consistency with the thermodynamical parameterization scheme of Arakawa and Schubert (1974).The parameterization is tested with observations of GATE74, Phase III. The data are processed on a B/C-scale grid (55km) in a region within 9N and 16N, and between 21W and 27W, and with a vertical resolution of 41 levels. The parameterization results correspond to the observed patterns, especially in situations with strong large-scale wind shear. The findings suggest that certain large-scalle flow regimes provoke convective scale momentum generation rather than redistributing large-scale momentum by convective circulations.With 10 Figures     

Spatial structure of a jet flow at a river mouth

The present work concentrates on the latest data measured in the Jordan river flow in lake Kinneret. Spectral characteristics of fluctuating velocity components have been obtained and processed. The three-dimensional structure of turbulence along the flow has been described. The main features of the jet flow turbulence in the river mouth are: a) The supply of turbulent energy changes due to different mechanisms along the flow. b) The structure of turbulence formed in the river decays rapidly along the flow, and c) In the sand area and beyond it, a significant generation of turbulent energy occurs. Quantitative estimations of the above effects were carried out.     

Atmospheric dispersion of a heavier-than-air gas near a two-dimensional obstacle

Flow over a two-dimensional obstacle and dispersion of a heavier-than-air gas near the obstacle were studied. Two species, one representing air and the other representing the heavier-than-air gas were treated. Equations for mass and momentum were cast in mass-averaged form, with turbulent Reynolds stresses and mass fluxes modeled using eddy-viscosity and diffusivity hypotheses. A two-equation k- turbulence model was used to determine the effective turbulent viscosity. Streamline curvature and buoyancy corrections were added to the basic turbulence formulation. The model equations were solved using finite difference techniques. An alternating-direction-implicit (ADI) technique was used to solve the parabolic transport equations and a direct matrix solver was used to solve the elliptic pressure equation.Mesh sensitivities were investigated to determine the optimum mesh requirements for the final calculations. It was concluded that at least 10 grid spaces were required across the obstacle width and 15 across the obstacle height to obtain valid solutions. A non-uniform mesh was used to concentrate the grid points at the top of the obstacle.Experimental measurements were made with air flow over a 7.6 by 7.6 cm obstacle in a boundary-layer wind tunnel. Smoke visualization revealed a low-frequency oscillation of the bubble downstream of the obstacle. Hot-wire anemometer data are presented for the mean velocity and turbulent kinetic energy at the mid-plane of the obstacle and the mid-plane of the downstream recirculation bubble. A single hot-wire probe was found to be suitable for determining mean streamwise velocities with an accuracy of 11 %. The downstream recirculation bubble was unsteady and had a length range from 3 to 8 obstacle lengths.The experimental results for flow over the obstacle were compared with numerical calculations to validate the numerical solution procedure. A sensitivity study on the effect of curvature correction and variation of turbulence model constants on the numerical solution was conducted. Calculations that included the curvature correction model gave a downstream recirculation bubble length of 5.9 obstacle lengths while excluding the correction reduced this length to 4.4.In the second part of the study, numerical calculations were performed for the dispersion of a heavier-than-air gas in the vicinity of the two-dimensional obstacle. Characteristics of an adiabatic boundary layer were used in these calculations. The densities of the contaminant gases were 0, 25 and 50% greater than the air density. Calculations were performed with the contaminant injection source upstream and downstream of the obstacle.Use of the pressure gradient model reduced the size of the dense gas cloud by as much as 12%. The curvature correction model also affected the cloud expanse by reducing the effective turbulent viscosity in the downstream recirculation bubble. The location of the injection source had the largest impact on the cloud size. The area of the cloud within the 5 % contour was three times larger for downstream injection than for upstream injection.