Atmospheric electrical measurements in the Hawaiian islands

Summary An exploration of the electrical properties of the atmosphere on and above the island of Hawaii, as indicated by a portable corona current unit, is described. A 30 foot telescopic mast having a radioactive probe mounted on an insulated bushing and connected by shielded cable to a sensitive microammeter was used. Corona currents were measured at a number of geographic locations ranging from sea level under conditions of heavy surf to the 10,000 foot level on Mauna Kea several thousand feet above the exchange layer, and over the land and ocean in a light plane. Observations were made under clear, cloudy and rainy conditions. Fair weather and cloudy conditions gave currents from air to earth of positive sign. With warm rain falling the currents had a negative sign and increased in value with intensity of precipitation. In several instances indications of incipient discharges similar to that observed in mild lightningstorms were noted.The island of Hawaii has many desirable features to recommend it for an extensive research program in atmospheric electricity. A simple and inexpensive approach to inaugurating such a program is suggested.     

Beitrag zur Kenntnis indischer Laterite

Zusammenfassung Es wurden zwei indische Lateritprofile untersucht. Die Lateritproben wurden soweit unverfestigt, in Korngrößenklassen zerlegt. Mit röntgenographischen. differentialthermoanalytischen und optischen Methoden wurde der Mineralbestand quantitativ bestimmt. Die Änderungen des Mineralbestandes und die Änderungen der Mineralverteilung wurde in den Lateritprofilen verfolgt.Die Lateritprofile sind auf quarzhaltigen Gesteinen, einem grobkörnigen Granit und einem feinkörnigen Quarz-Glimmer-Sandstein, entstanden. Als Ursache der Lateritbildung ist bei beiden Profilen die Verwitterung und Kaolinisierung des Ausgangsgesteins anzusehen. Bei dem Granit wurden die Feldspäte sowie die Hornblende und der Biotit, bei dem Sandstein wurde der Muskowit kaolinisiert. Der Quarz wurde mehr oder weniger stark korrodiert.Durch die Anreicherung von oxydischen und hydroxydischen Eisenmineralen in bestimmten Zonen der Verwitterungsprofile kam es zur Ausbildung typischer Lateritprofile mit konkretionsführenden bzw. pisolithischen Horizonten. Die Anreicherung von Eisenmineralen in diesen Horizonten ist durch Zufuhr von Eisen aus Verwittrungslösungen erfolgt. Das Eisen entstammt bei dem ersten Profil den verwitternden eisenhaltigen Mineralen des Granites, der Hornblende und dem Biotit. Bei dem zweiten Profil ist die Herkunft des Eisens aus verwitternden hämatitreichen Rindern des Sandsteines abzuleiten. An hydroxydischen Aluminiummineralen sind in beiden Lateritprofilen nur geringe Mengen Diaspur vorhanden.Auflösung von Kaolinit, Wanderung der Kaolinsubstanz und Neubildung von Fireclaymineral wurde in beiden Profilen nachgewiesen.     

Veränderungen an Zirkon und Turmalin in Buntsandstein und Keuper

Zusammenfassung Es wird über Turmalin- und Zirkon-Veränderungen durch Auflösung und Neukristallisation berichtet. Unter Anführung von Beobachtungen anderer Autoren wird von der Verfasserin angenommen, daß es sich um sedimentäre Neubildungen handelt.     

Heidornit Na2Ca3[Cl · (SO4)2 · B5O8(OH)2] ein neues Bormineral aus dem Zechsteinanhydrit Mit einer röntgenographischen Untersuchung

Ohne Zusammenfassung     

Der prägranitische Bau des Gneisgebirges im südlichen Schwarzwald und seine Ableitung aus dem Fremdgesteinsinhalt der hybriden Granite

Ohne Zusammenfassung     

Quantitative Auswertung einfacher Gefügediägramme

Zusammenfassung Bei einfachen Gefügediagrammen mit nur 1 Maximum wird eine elementar ausführbare rechnerische Bestimmung des Schwerpunktvektors mit Hilfe von Auszählnetzen durchgeführt. Seine wahrscheinlichkeitstheoretische Zuverlässigkeit kann aus Nomogrammen; die nach der Theorie vonR. A. Fisher berechnet wurden, abgelesen werden. Die Größe des Schwerpunktvektors, umgerechnet auf Prozent der idealen. Parallelorientierung, ist ein unmittelbares Maß der Regelungsschärfe und daher auch von praktischem Interesse. Anwendungsmöglichkeiten und Grenzen der rechnerischen Auswertung werden aufgezeigt. Ein Beispiel erläutert die Besonderheiten des Verfahrens.     

Organization of convection and monsoon forecasts

Summary In this paper we address the issue of monsoon forecasts in relation to the organization of convection. Given a physical initialization procedure, within a data assimilation, it is possible to use the detailed distribution of rainfall from mesoconvective precipitating elements to define the initial state of a global model. If that is carried out using a very high resolution model then the initial state can carry within it an organization of convection within the resolvable scales. Then the impact of physical initialization on the maintenance and prediction of tropical weather such as the monsoon can be determined. Lacking such an initialization, one can expect the convectively driven energetics to be biased, and a slow degradation of the forecasts can follow. Several examples of forecasts at different resolutions are discussed here. The main findings of this study are that improved forecast results are obtained when physical initialization is invoked where the observed rain and the model resolution are comparable, i.e. the footprint of the highest resolutions rainfall estimates obtained from satellite based data sets (principally we use the SSM/I instrument over the oceans). At this resolution, we note that the model is able to carry an organization of convection in the initialization and in the forecasts through the medium-range time scale.We have compared our results of monsoon studies at a resolution T255 with those at resolution T62. The transform grid separation at the resolution T255 is approximately 50 km and at the resolution T62, it is approximately 200 km. We find that the model at the higher resolution (T255) performs better and has more realistic energy conversions for the convectively driven synoptic scale monsoon.An organization of convection, at the synoptic scales, is not seen in the forecasts at lower resolutions, T62, where the rainfall patterns are generally much broader and tend to be more zonal. Such organization appears more realistic at the resolution T255. Variances of the energy conversion, calculated in the two-dimensional spectral space, from physically initialized short range forecasts at the higher resolution are seen to be largest on the scales of the monsoon. Similar calculations for the reanalyzed fields at lower resolutions show the spectral distribution of variances to be biased towards local Hadley scale overturnings.With 12 Figures     

Rain rate estimation from a synergetic use of SSM/I, AVHRR and meso-scale numerical model data

Summary In this paper a retrieval technique for estimating rainfall rates is introduced. The novel feature of this technique is the combination of two satellite radiometers — the Special Sensor Microwave/Imager (SSM/I) and the Advanced Very High-Resolution Radiometer (AVHRR) — with mesoscale weather prediction model data. This offers an adjustment of the model atmospheres to reality which is necessary for calculating brightness temperatures that can be compared with microwave satellite measurements.In sensitivity studies it was found that the estimation of precipitation is determined to a high degree by the particle size distribution of rain and snow, especially by the size distribution of solid hydrometeors. These studies also reveal the influence of the knowledge of the correct cloud coverage inside a SSM/I pixel and the importance of using a realistic temperature profile instead of using standard atmospheres.The retrieval technique is based on radiative transfer calculations using the model of Kummerow et al. (1989). The algorithm consists of two parts: First Guess (FG) brightness temperatures for the SSM/I frequencies are generated as a function of the cloud top height and the cloud coverage, derived from AVHRR data and predictions from a meso-scale model. The rainfall rate of different types of clouds containing raindrops, ice particles and coexisting ice and water hydrometeors is then calculated as a function of the cloud top height. As an example, a strong convective rain event over the western part of Europe and over the Alps is taken to evaluate the performance of this technique. Good agreement with radar data from the German Weather Service was achieved. Compared to statistical rainfall algorithms, the current algorithm shows a better performance of detecting rainfall areas.With 12 Figures     

Determination of predevelopment denudation rates of an agricultural watershed (Cayaguás River, Puerto Rico) using in-situ-produced Be in river-borne quartz

Accurate estimates of watershed denudation absent anthropogenic effects are required to develop strategies for mitigating accelerated physical erosion resulting from human activities, to model global geochemical cycles, and to examine interactions among climate, weathering, and uplift. We present a simple approach to estimate predevelopment denudation rates using in-situ-produced cosmogenic ¹⁰Be in fluvial sediments. Denudation processes in an agricultural watershed (Cayaguás River Basin, Puerto Rico) and a matched undisturbed watershed (Icacos River Basin) were compared using ¹⁰Be concentrations in quartz for various size fractions of bed material. The coarse fractions in both watersheds bear the imprint of long subsurface residence times. Fine material from old shallow soils contributes little, however, to the present-day sediment output of the Cayaguás. This confirms the recent and presumably anthropogenic origin of the modern high denudation rate in the Cayaguás Basin and suggests that pre-agricultural erosional conditions were comparable to those of the present-day Icacos.