The dynamics and thermodynamics of precipitation loading

A one-dimensional, time-dependent numerical cloud model is used to analyze the factors in the dynamic and thermodynamic equations which lead to a steady-state or nonsteady-state solution for the cloud vertical motion, buoyancy, precipitation, and cloud water fields. ‘Bulk water’ microphysical techniques are used for the cloud, rain, and hail variables. An atmospheric sounding from a severe storm situation is used as initial and environmental conditions, yielding model updrafts of 40 m sec^?1 maximum and more than 10 m sec^?1 over the entire cloud region. ‘Early conversion’ of the cloud water to rain leads to loading of lower portions of the updraft by rain, the formation of appreciable amounts of hail by freezing of the supercooled rain, and subsequent loading of the middle and upper portions of the updraft so that the updraft erodes throughout the cloud depth and the cloud dissipates, yielding a vigorous rain shower. A delay in the conversion of the cloud water to rain results in a steady-state solution, no rain or hail falling through the updraft. A two-dimensional cloud simulation of this same case shows rain and hail in the upper cloud regions recycled in the two-dimensional flow into the updraft near cloud base and a breakdown of the updraft with resultant rainout (negligible hail reaching the ground). The breakdown of the updraft has profound effects on the temperature field within the cloud, causing the lapse rate to deviate from the steady-state condition and approach the initial environmental conditions. The results emphasize the fact that the local change in temperature (and other dependent variables as well) is not independent of the vertical velocity, in general. This has implications for the interpretation of measurements made within clouds.     

Synoptic variations in the chemical composition of atmospheric precipitation

Summary A study of the chemical composition of monthly precipitation samples from a number of stations in Sweden brings out the existence of significant variations in the relative proportions of chlorides and sodium depending upon the general character of the prevailing circulation. In maritime westerly flows the weight ratio of chloride to sodium decreases eastward to values which lie far below that value characteristic of sea water. In precipitation falling from arctic or polar continental air masses the chloride component is almost completely absent. The highest amounts of chlorides relative to sodium are observed in precipitation from warm and most air masses reaching Sweden from the south or southeast.Significant variations are observed also in the yearly means of the chloride to sodium ratio depending upon the dominance of maritime or continental air currents.A sketch map of the «average» chloride concentration in European precipitation prepared from miscellaneous older data lends support to the results of the analysis of the monthly data. The separation of the chemical components indicated by this study would seem to be of considerable geochemical interest since it would permit different maritime salts to be deposited in widely separated parts of the continents.The full paper will be published in «Tellus», VII (1955), 1.

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Zusammenfassung Ein Studium der chemischen Zusammensetzung von Proben des monatlichen Niederschlages einer Anzahl von Beobachtungsstationen in Schweden deckt die Existenz von deutlichen Schwankungen im relativen Verhältnis von Chlor und Natrium auf, welche vom allgemeinen Charakter der vorherrschenden Zirkulation abhängen. In maritimen westlichen Strömungen nimmt das Gewichtsverhältnis von Chlor zu Natrium gegen Osten zu auf Werte, welche weit unterhalb des charakteristischen Betrages für Meerwasser liegen, ab. Im Niederschlag, welcher aus arktischen oder polar-kontinentalen Luftmassen stammt, fehlt die Chlor-Komponente beinahe vollständig. Der höchste Betrag von Chlor relativ zu Natrium wurde im Niederschlag aus warmen und den meisten Luftmassen, welche Schweden vom Süden und Südosten erreichen, gefunden.Deutliche Schwankungen wurden auch in den Jahresmitteln des Verhältnisses Chlor zu Natrium beobachtet, welche von der Vorherrschaft der maritimen oder kontinentalen Luftströmungen abhängen.Eine schematische Karte der «mittleren» Chlor-Konzentration im Europäischen Niederschlag, welche mit Hilfe von verschiedenen älteren Daten entworfen wurde, unterstützt die Resultate der Analyse der Monatswerte. Die Trennung der chemischen Komponenten, welche durch diese Untersuchung angedeutet wird, scheint von beträchtlichem Interesse für die Erdchemie zu sein, da auf diese Weise verschiedene maritime Salze in weit auseinander liegenden Teilen der Kontinente abgelagert würden.Die ausführliche Arbeit wird in der Zeitschrift «Tellus», VII (1955), 1 veröffentlicht werden.

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Presented by Mr. ClaesRooth, Institute of Meteorology, University of Stockholm, Lindhagensgatan 124v,Stockholm (Sweden).     

Effect of synthetic fertilizers and atmospheric precipitation on nitrogen enrichment in surface waters

The increase of the nitrate concentration in surface waters used as water supply resources has been investigated with a view to the effects of agricultural activities and atmospheric precipitation. The nitrate concentration increased beyond the acceptable limit for infants after 1975, when due to the permanent augmentation of the synthetic fertilizer rates the organic humus quantities decreased to a minimum. The variability of nitrate concentrations in atmospheric precipitation is dependent on the magnitude of precipitation and the intensity of industry in the given region. At an average value of atmospheric precipitation the nitrogen value in agricultural regions varies within 6 to 12 kg · ha^?1 · a^?1, in regions with extended industries up to 24 kg · ha^?1 · a^?1.     

构造和气候共同控制下的藏南热隆盆地中更新世以来的演化

热隆盆地是亚东－谷露裂谷系南部, 由宁金抗沙西麓断裂控制的断陷盆地, 根据野外地质调查、 遥感(RS)和数字高程模型(DEM)分析, 盆地内发育有三期洪积扇, 形成时代分别在中更新世中期(第一期)、 中更新世中期至晚更新世早期(第二期)、 晚更新世晚期(第三期)。 这三期洪积扇的发育分别对应于间冰期和间冰阶的高温大降水时期, 表明在第四纪以来, 由于间冰期与间冰阶期的到来, 温度升高, 降雨量增加, 地表径流作用增强, 先成洪积扇被破坏, 新洪积扇形成。 盆地内自中更新世中晚期以来剥蚀程度自北向南减弱, 表明在整体抬升的背景下, 由于宁金抗沙西麓断裂的活动, 使得盆地北部基岩抬升速率大于南部, 形成自北向南的掀斜。     

华北降水年代际变化特征及相关的海气异常型

利用近50年华北地区26个站逐月降水观测资料和全球大气海洋分析资料,分析了华北降水的年代际变化特征及其和全球海气系统年代际变化的关系.对华北降水距平指数变化分析表明,近50年来华北降水具有减少的总体趋势,叠加在该趋势之上的是年代际变化,其中1965年和1980年发生了两次跃变,使得20世纪80年代干旱尤为严重.在对华北地区降水年代际变化特征分析的基础上,揭示了与华北降水年代际异常相伴随的大气环流和上层海洋热力异常型.结果表明,华北降水年代际异常与太平洋上层海洋热力状况异常有显著关系,主要表现为太平洋年代际振荡（PDO）与华北降水异常的相关.在年代际时间尺度上,华北干旱与上层海洋热力及大气环流异常的配置关系如下：当华北地区干旱时,则热带中东太平洋海温偏高,北太平洋中部海温偏低,即太平洋上主要表现为PDO暖位相,全球大部分地区（包括华北地区）气温偏高,青藏高原地区气温偏低,日本北部及东西伯利亚气压异常偏低,华北及其以南大片地区气压偏高,华北地区由异常西北风控制,不利于水汽向华北地区输送.     

Upward flux of RaB and RaC in the planetary boundary layer as controlled by atmospheric microstructure

Summary Vertical mixing and transport processes are studied, and their variation as influenced by atmospheric fine-structure conditions investigated, using data gathered from simultaneous measurements of RaB and RaC concentration in the ambient air at three mountain stations located close to each other horizontally, but at markedly differing levels (730, 1780 and 2960 m). RaB was used as a tracer on account of the high sensitivity to variations of vertical-mixing activity evidenced by RaB abundance figures. Strong inversions between 700 and 2500 m a.s.l. create a zero condition at the higher level, where only 0.1% of the low-level RaB reading obtains; active turbulent mixing, on the other hand, leads to nearly equal RaB readings at the two levels. The vertical gradient of concentration of RaB is used to compute mean vertical-mass-exchange coefficients; the latter are studied in their relation to atmospheric structure characteristics. Statistical studies indicate that the barring effect of inversions is related solely to the magnitude of the inverse temperature gradient. Problems of radioactive equilibrium RaB-RaC are discussed, and the significance of aerosol particle size taken into consideration.

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Zusammenfassung Simultane Messungen der RaB- und RaC-Konzentration der Luft an 3 Bergstationen von geringem horizontalem Abstand aber mit relativ grossen Höhenunterschieden (Stationsniveau rund: 700, 1800 und 3000 m a.s.l.) werden benutzt um die vertikalen Mischungs-und Transportvorgänge und ihre Abhängigkeit von der atmosphärischen Feinstruktur zu studieren. Die RaB-Konzentration der Luft reagiert nämlich sehr empfindlich auf Schwankungen der Austauschintensität. Im Falle einer kräftigen Inversion zwischen 700 und 2500 m a.s.l. fällt die RaB-Konzentration über dieses Höhenintervall hinweg auf 0,1% des Basiswertes ab, bei turbulentem Austausch herrscht fast Konzentrationsgleichheit. Aus den vertikalen RaB-Konzentrationsgradienten werden mittlere vertikale Austauschkoeffizienten berechnet und diese zur atmosphärischen Struktur in Beziehung gesetzt. Es zeigte sich dabei, dass die Sperrwirkung einer Inversion nur durch die Steilheit der Temperaturänderung im Inversionsbereich bedingt ist. Probleme des radioaktiven Gleichgewichts zwischen RaB und RaC werden diskutiert. Auch die Bedeutung der Aerosolpartikelgrösse wird mit in Betracht gezogen.

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Paper presented at the XIVth General Assembly of the IUGG, meeting of the ICACR, Luzern, October 1967. The work has been sponsored by European Research Office, US Army, and Department of Defence of FRG     

Input of chemical substances with atmospheric precipitation onto the territory of Karelia

The chemical composition of atmospheric precipitation over the entire territory of Karelia is characterized on the basis of snow samples taken during the periods of maximum snow storage in 1996–2000. The concentration of chemical elements and their fallouts are considered within the northern, central, southern, and eastern regions of Karelia. The aero-technogenic effect of industrial centers of Karelia and the Archangelsk Province on the chemical composition of atmospheric precipitation is analyzed. The above material is generalized in the form of average statistical characteristics of the chemical fallouts of mineral, organic, and biogenic substances, heavy metals, and strong acids.     

Comprehensive study on stability of deep crust and unstable behavior of earthquake source by both failure mechanism and frictional sliding mechanism

In this paper the relation between fault movement and stress state in deep crust is discussed, based on synthetic analysis of the crustal stresses measured over the world and the concerned data of focal mechanism. Using Coulomb criterion for shear failure and frictional slip, analytical expressions for estimating stabilities of intact rock and existing fault in the crust and for identifying the type of faulting (normal, strike-slip or thrust fault) are derived. By defining the Failure FunctionF _m and the Fraction FunctionF _f, which may describe steadiness of crustal rock and existing fault, respectively, a synthetic model is set up to consider both fracturing mechanism and the sliding mechanism. By this model, a method to study stability and unstable behavior of crustal rock and fault at different depths is given. According to the above model, quantitative study on the crustal stability in the North China plain is made in terms of the measured data of hydraulic fracturing stress, pore-fluid pressure, terrestrical heat flow in this region. The functionsF _m andF _f and the shear stresses on faults with different strike angle and dip angle at various depths in this region are calculated. In the calculation the constraint condition of fault movement obeys Byerlee’s Law, and the depth-dependent nonlinear change in the vertical stress due to inhomogeneity of crustal density and the high anomalous pore-fluid pressure in deep crust of this region are considered. The conclusions are: the unstable behavior of the crust in the North China plain is not failure of crustal rock but slip on existing fault; the depth range where stick-slip of fault may happen is about from 8 to 20 km or more; stability of steep fault is lower than that of gentle sloping fault; the shear stresses in the range where may occur stick-slip are nearly horizontal; the steep faults trending from NNE to NE in this region are liable to produce strong earthquakes, whose co-seismic faultings are, for the most part, right lateral slip; the change in pore-fluid pressure in depth remarkably affects the stability of the crust and the increase in pore-fluid pressure, therefore, would be an important factor exciting strong earthquake in this region. The above theoretical inferences are consistent with the data measured in this region. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologia Sinica,13, 450–461, 1991. This work is supported by Chinese Joint Seismological Science Foundation.     

与气压有关的地电场特征及机理研究

使用宁夏四个地电台站记录的地电场数据,研究其变化特征、频谱特征、与区域气压变化的关系及测量方向与附近断裂走向的关系。研究结果显示：部分地电场具有日变化特征,同时也具有气压非周期性变化特征,这种特征与气压变化呈负相关,当场地裂隙优势方位与附近断裂带方位呈近似垂直或较大夹角时,测向与附近断裂走向近垂直的地电场与气压相关性较高。分析认为地电场具有气压非周期变化特征是因为测量位置基岩孔隙的渗透率与附近断裂裂缝的渗透率不同,流体渗流过程中气压系统变化引起的流体“窜流”所致。     

A purely hydrodynamic mechanism for atmospheric banding and continental drift

A periodic rotating gravitational force will produce purely hydrodynamic flow fields on the outside and inside of rotating spheres in the laboratory which are compatible with the observable banded atmospheric structure of Jupiter, Venus, and possibly other planets, and the apparent motions of lithospheric plates on the surface of the earth. Thermal gradients are not required to produce convective flow in this system.     

非绝热加热对大气局地扰动位能的影响和机理

本文运用统计相关和奇异值分解方法,系统地考察了非绝热加热对大气局地扰动位能的影响特征和机理问题.分析结果表明,热带地区海表温度异常和扰动位能的耦合相关特征与厄尔尼诺和南方涛动变率的关系密切,扰动位能在热带外地区的耦合模态空间型呈现出与北太平洋—北美大气遥相关型极为相似的分布特征.通过进一步考察大气中视热源与扰动位能的耦合特征,发现在低纬地区仍主要反映了厄尔尼诺和南方涛动的影响机制,在热带外地区,视热源异常的耦合模态则表现出与北半球环状模类似的特点,这表明热带外地区大气的局地能量有效性与热带非绝热加热的遥强迫以及局地性热源加热强迫有着极为密切的联系.     

Stable isotopes of atmospheric water vapour and precipitation in the northeast Qinghai‐Tibetan Plateau

Stable water isotopes (δ¹⁸O and δ²H) are an important source signature for understanding the hydrological cycle and altered climate regimes. However, the mechanisms underlying atmospheric water vapour isotopes in the northeast Qinghai‐Tibetan Plateau of central Asia remain poorly understood. This study initially investigated water vapour isotopic composition and its controls during the premonsoon and monsoon seasons. Isotopic compositions of water vapour and precipitation exhibited high variability across seasons, with the most negative average δ¹⁸O values of precipitation and the most positive δ¹⁸O values of water vapour found during the premonsoon periods. Temperature effect was significant during the premonsoon period but not the monsoon period. Both a higher slope and intercept of the local meteoric water line were found during the monsoon period as compared with in the premonsoon period, suggesting that raindrops have been experienced a greater kinetic fractionation process such as reevaporation below the cloud during the premonsoon periods. The δ²H and δ¹⁸O signatures in atmospheric water vapour tended to be depleted with the occurrence of precipitation events especially during the monsoon period and probably as a result of rainout processes. The monthly average contribution of evaporation from the lake to local precipitation was 35.2%. High d‐excess values of water vapour were influenced by the high proportion of local moisture mixing, as indicated by the gradually increasing relative humidity along westerly and Asian monsoon trajectories. The daily observation (observed ε) showed deviations from the equilibrium fractionation factors (calculated ε), implying that raindrops experienced substantial evaporative enrichment during their descent. The average fraction of raindrops reevaporation was estimated to be 16.4± 12.9%. These findings provide useful insights for understanding the interaction between water vapour and precipitation, moisture sources, and help in reconstructing the paleoclimate in the alpine regions.     

北京城市化对夏季大气边界层结构及 降水的月平均影响

为克服针对一次或几次天气过程研究城市化对边界层结构及降水影响的局限性,尝试研究北京城市化对夏季大气边界层结构及降水的月平均影响,本文首先总结了2006年8月份的主要天气过程,分析了气象站观测的10 m高度风速、2 m高度气温、2 m高度比湿和24 h降水的月平均分布特征,然后利用WRF/Noah/UCM模拟系统,进行了该月30个个例的高分辨率数值模拟及检验分析,并通过多组不同城市化情景的敏感性试验对比分析了城市化对夏季大气边界层结构及降水的月平均影响.研究表明:本文所用对高分辨率数值模拟结果进行月平均的方法可以较合理地模拟出城市化对大气边界层结构及降水的影响,并再现观测到的各站风频差异.8月份,北京城市化对气温的影响高度白天约为800 m,近地面气温升高1℃以上;夜间约为200 m,对近地面气温的影响达到最大(1.4℃以上).白天,城市化使城市及下风向的一些区域风速略有减小;夜间,城市及周边区域200 m以下风速明显减小,且在100 m左右高度处风速减小最明显,减小达0.8 m/s以上.城市化白天使700 m以下比湿减小,近地面处减小达1.2g/kg以上,夜间使近地面空气比湿略有减小.城市化对城市区域平均降水量的影响随城市发展的不同阶段而不同.初步模拟分析表明, 北京城市化已使上风向区域以及城区三环以内降水量减少,海淀和昌平降水明显增加.     

III: Methods of correcting for systematic errors in atmospheric precipitation measurements in Czechoslovakia

The methods of correcting for systematic errors in precipitation measurements using the Czechoslovak gauge METRA 886 are presented. This gauge has an orifice area of 500 cm² and is elevated 1 m above the ground. The wetting correction amounts to 0.1–0.2 mm per measurement. The evaporation correction ranges from 3 per cent in frost-free periods to 10 per cent in frost periods. The wind-induced correction amounts to 5 per cent for rain and 45 per cent for snow. The total sum of corrections on average 10–15 per cent per year in lower localities.     

Regionalization of precipitation characteristics in the Canadian Prairie Provinces using large-scale atmospheric covariates and geophysical attributes

Observed data at most stations are often inadequate to obtain reliable estimates of many hydro-meteorological variables that not only define water availability across a region but also the vulnerability of social infrastructure to climatic extremes. To overcome this, data from neighboring sites with similar statistical characteristics are often pooled. The pooling process is based on partitioning of a larger region into smaller sub-regions with homogeneous features of interest. The established approaches rely heavily on statistics computed from observed precipitation data rather than the covariates that play a significant role in modulating the regional and local climate patterns at various temporal and spatial scales. In this study, a new approach for identifying homogeneous regions for regionalization of precipitation characteristics is proposed for the Canadian Prairie Provinces. This approach incorporates information about large-scale atmospheric covariates, teleconnection indices and geographical site attributes that impact spatial patterns of precipitation in order to delineate homogeneous precipitation regions through combined use of multivariate approaches—principal component analysis, canonical correlation analysis and fuzzy C-means clustering. Results of the analyses suggest that the study area can be partitioned into five homogeneous regions. These partitions are validated independently for homogeneity using statistics computed from monthly and seasonal precipitation totals, and seasonal extremes from a network of observation stations. Furthermore, based on the identified regions, precipitation magnitude-frequency relationships of warm and cold season single- and multi-day precipitation extremes, developed through regional frequency analysis, are mapped spatially. Such estimates are important for numerous water resources related activities.     

新疆夏季降水年代际转型的归因分析

本研究针对我国内陆新疆地区在20世纪80年代末出现由暖干向暖湿的年代际转型,从大气环流因子进行归因分析.结果显示,位于东亚沿海地区的东亚-太平洋型遥相关波列(EAP)的强度和位置的年代际加强和偏移对于新疆地区此次气候的干湿转型具有重要贡献.转型之前EAP强度偏弱,位置相对偏东,对新疆夏季降水变化没有明显贡献,且影响新疆夏季降水发生的主要环流系统是位于中纬度欧亚大陆上空的异常纬向波列.转型后EAP强度偏强,位置相对前期向西偏移,因此从西北太平洋向我国内陆地区的异常水汽输送显著增强,使得新疆地区大气含水量增加,从而导致20世纪80年代末以后新疆夏季降水的增加.     

Systematic measurement of the radioactivity of atmospheric precipitation and evaluation of the artificial radioactivity of the atmosphere

Резюме В статье приводится описание методики измерений искусственной радиоактивности осадков. В результате измерений более 90 образцов бЫло доказано, что здесь мЫ имеем дело с искусственной радиоактивностью, вЫзЫваемой наличием продуктов распада образующихся в результате опЫтов с атомнЫм оружием. Доказательством этого служит прежде всего убЫвание активности испарений с временем. Абсолютная оценка показала, что здесь речь идет об активности порядка 10⁻¹⁰–10⁻⁹ кюру/л. в воде осадков. ПроведеннЫе работЫ показали, насколько важнЫми могут бЫть подобнЫе измерения для метеорологических целей, но в особенности для фпзики облаков и осадков.

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Address: Vojenská lékařská akademie J. Ev. Purkynê, Hradec Králové.

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Address: Geofysikální ústav ĈSAV, odd. meteorologie, Hradec Králové 8.     

扰动位能与大气环流异常的耦合关系及机理研究

本文在前期局地扰动位能理论工作基础上,进一步着眼于扰动位能与大气环流异常的关系和机理问题,采用奇异值分解(SVD)方法分析了扰动位能与高、中、低层大气动能的耦合相关模态以及年际变率情况,同时考察它与作为大气质量分布的海平面气压之间的相关关系,并从物理上初步探讨了扰动位能与大气动能以及质量的相关机理问题.结果表明,扰动位能自身变率的第一模态同时也是与大气环流异常场耦合变化的主要模态,与之相对应的大气动能和质量场的主模态也是其自身变率的支配模态,说明它们之间存在相互制约的物理机制.而且,热带外地区大气环流主模态特征的形成,与扰动位能兼具全球尺度纬向对称结构和局地尺度纬向非对称性密不可分.另外,冬季南北半球环状模指数与扰动位能的前两阶矩存在非常好的相关关系,而在夏季这种关系明显削弱,仅存在于南半球.     

A symmetrical aspiration capacitor for the simultaneous recording of atmospheric ions of both polarities

Summary With the ordinary aspiration-capacitor, ions of only one polarity can be detected, and for the simultaneous measurement of ions of both polarities, two such counters are necessary. For the investigation of the transient phenomena in an aspiration-capacitor, a symmetrical plate capacitor has been constructed. When each of the plates is connected to a separate electrometer, ions of one polarity can be recorded by one of the electrometers connected to one of the plates and ions of the other polarity by the electrometer connected to the other plate. The advantage of the symmetrical aspiration-capacitor described is that ions of both polarities contained in the same air volume can be simultaneously recorded.

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Zusammenfassung Mit den üblichen Aspirationskondensatoren können nur Ionen des einen Vorzeichens gemessen werden, und wenn man beide Polaritäten gleichzeitig erfassen will, sind zwei solcher Kondensatoren nötig. Zur Untersuchung der Einschaltvorgänge in einem Aspirationskondensator wurde ein symmetrischer Plattenkondensator entworfen. Wird jede der beiden Platten mit einem Elektrometer verbunden, so können die Ionen des einen Vorzeichens mit einem der Elektrometer, die mit der einen Platte verbunden sind, gemessen werden, während die Ionen des anderen Vorzeichens mit dem mit der anderen Platte verbundenen Elektrometer gemessen werden. Der Vorzug des symmetrischen Aspirationskondensators ist, dass Ionen beider Vorzeichen in dem gleichen Luftraum gleichzeitig gemessen werden können.