Observational effort to record Fresnel patterns during a total solar eclipse

Summary The observation of Fresnel diffraction patterns at 2nd and 3rd contact and efforts to correlate the time elements of a total solar eclipse at low elevation are discussed. The measurements were intended to determine atmospheric refraction at three optical wavelengths. A laboratory model of the system sun-moon-earth was employed for testing the recording instruments at the fast response times that are necessary for such observations.

---

Zusammenfassung Diskutiert werden die Vorbereitungen zur Beobachtung von Fresnelschen Beugungsstreifen im Mondschatten, wenn 2. und 3. Kontakt einer Sonnenfisternis in die Sonnenaufgangszone fallen (streifender Lichteinfalt). Bei Kenntnis des Mondrandes kann man die Auswertung der Beugungsfiguren mit den Konjunktionszeiten korrelieren. Vergleiche mit den errechneten Ephemeriden ermöglichen eine Bestimmung der atmosphärischen Refraktion. Ein Modell diente zur Prüfung der Beobachtungsapparaturen.

     

Spontane Bildung negativer Raumladungen in einem maritimpolaren Luftkörper mit hoher Aerosolkonzentration

Zusammenfassung In einem maritim-tropischen Luftkörper wurde während mehrerer Tage beobachtet, dass sich in 50–200 m über dem Boden spontan negative Raumladungen ausbilden, wenn kalte Hangabwinde in die bodennahe Luftschicht eindringen und sich mit der vorher vorhanden gewesenen erwärmten Luft turbulent vermischen. Der «luftelektrisch aktivierbare» Luftkörper zeichnete sich durch extrem hohe Aerosolkonzentration aus. Das Partikelspektrum war in Richtung auf grobe Aerosolkomponenten verschoben.

---

Summary Spontaneous formation of negative space charges 50–200 m above the ground has been observed for several consecutive days in a warm maritime (mT) air mass penetrated by cold mountain-slope winds; the cold air underwent turbulent mixing with the pre-existing warm air. The electrifiable airspace was characterized by an extremely high aerosol concentration, with the size distribution spectrum shifted from the normal toward a significantly increased incidence of coarse particles.

---

---

Physikalisch-Bioklimatische ForschungsstelleGarmisch-Partenkirchen der Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung.     

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.

---

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.

---

---

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     

The problem of heat flow density determination from inaccurate data

We present an inverse method for processing rough data from oil wells in order to evaluate the heat flow density. Assuming that the evaluations of temperatures and thermal resistivities present gaussian uncertainties, we give formulas for computing the optimal value of the heat flow density and its standard deviation. A synthetic example, using likely assumptions on various uncertainties, leads to the prediction that a standard deviation of about 10 mW m^?2 could apply to heat flow estimates from oil well data for typical situations.     

On the computation of area probabilities based on a spatial stochastic model for precipitation cells and precipitation amounts

A main task of weather services is the issuing of warnings for potentially harmful weather events. Automated warning guidances can be derived, e.g., from statistical post-processing of numerical weather prediction using meteorological observations. These statistical methods commonly estimate the probability of an event (e.g. precipitation) occurring at a fixed location (a point probability). However, there are no operationally applicable techniques for estimating the probability of precipitation occurring anywhere in a geographical region (an area probability). We present an approach to the estimation of area probabilities for the occurrence of precipitation exceeding given thresholds. This approach is based on a spatial stochastic model for precipitation cells and precipitation amounts. The basic modeling component is a non-stationary germ-grain model with circular grains for the representation of precipitation cells. Then, we assign a randomly scaled response function to each precipitation cell and sum these functions up to obtain precipitation amounts. We derive formulas for expectations and variances of point precipitation amounts and use these formulas to compute further model characteristics based on available sequences of point probabilities. Area probabilities for arbitrary areas and thresholds can be estimated by repeated Monte Carlo simulation of the fitted precipitation model. Finally, we verify the proposed model by comparing the generated area probabilities with independent rain gauge adjusted radar data. The novelty of the presented approach is that, for the first time, a widely applicable estimation of area probabilities is possible, which is based solely on predicted point probabilities (i.e., neither precipitation observations nor further input of the forecaster are necessary). Therefore, this method can be applied for operational weather predictions.     

南京市浅层地温场研究——基于分布式光纤测温技术

浅层地热能作为新型能源受到了国际国内的广泛关注,常规的电阻式温度传感器受电磁干扰,不适合长期在野外复杂环境中使用.本文应用抗干扰能力强的分布式光纤测温技术,对南京市19个百米深钻孔进行地温测量,获得了2018年冬季与2019年春季南京市浅层地下温度分布.综合南京市水文和地质条件,得出结论:浅层地温的变化相对于气温的变化...     

Thermal tracer testing in a sedimentary aquifer: field experiment (Lauswiesen,Germany) and numerical simulation

An active and short-duration thermal tracer test (TTT) was conducted in a shallow sedimentary aquifer at the Lauswiesen test site, near Tübingen, Germany. By injecting 16  m³ of warm water at 22°C, a thermal anomaly was created, which propagated along the local groundwater flow direction. This was comprehensively monitored in five observation wells at a few meters distance. The purpose of this well-controlled experiment was to determine the practicability of such a TTT and its suitability to examine hydraulic characteristics of heterogeneous aquifers. The results showed that the thermal peak arrival times in the observation wells were consistent with previous observations from alternative field testing such as direct-push injection logging (DPIL). Combined analysis of depth-dependent temperatures and peak arrival times, and comparison with a numerical heat transport model, offers valuable insights into the natural flow field and spatial distribution of hydraulic conductivities. The study was able to identify vertical flow focusing and bypassing, which are attributed to preferential flow paths common in such sedimentary sand and gravel aquifers. These findings are fundamental for further development of experimental designs of active and short-duration TTTs and provide a basis for a more quantitative analysis of advective and conductive transport processes.