Daily Weather Observations in Sixteenth-Century Europe

Thirty-two weather diaries written in astronomical calendars in central Europe in the late fifteenth and sixteenth centuries are presented and discussed. Systematic weather observations were promoted by the rise of planetary astronomy and its application in astro-meteorology. The practice of keeping weather diaries spread from Cracow (Poland) to Ingolstadt (Germany) and from there to other universities. The data obtained from these sources provided the backbone for setting up series of precipitation indices for Poland, Germany and Switzerland. Monthly statistics of days with precipitation, snowfall and frost were computed by counting the relevant entries in the most important diaries. The results were compared with either those obtained from instrumental measurements in the same place or with those from modern instrumental measurements in a neighbouring place. The final results show that autumn was considerably colder in the early sixteenth century. April was considerably drier and July was wetter during the period 1508-1531 than during 1901-1960. In order to highlight the impact of weather patterns on grain prices in a year of crisis, the timing of wet and dry spells in southern Poland and southern Germany is compared for the year 1529. Winters became 1.7°C colder from 1564 to 1576 and the month of July tended to be wetter than in 1901-1960. Details noted in the diaries kept between 1585 and 1600 by the astronomers Brahe (near Copenhagen) and Fabricius (in the Ostfriesland region of northwestern Germany) closely agree. It rained more often in June and July and temperatures dropped. The winter months were more frequently dominated by winds from easterly directions, the frequency of snowfall was higher and a deficit occurred in precipitation. This points to a higher frequency of high pressure in the Fennoscandian area with cold air advection from the east or northeast.     

Interaction between diapirism and sediment loading at the shelf-slope boundary,northwest Gulf of Mexico

During the last low stand of sea level, rivers and streams drained across the present northwestern Gulf of Mexico continental shelf depositing sediments in several shallow-water deltas near the present shelf-slope boundary. The weight of these wedges of prograded sediments triggered or augmented both subsidence of local depositional basins and upward movement of diapiric material around the basin edges. A depositional basin off the southwestern Louisiana coast records migration of the basinal axis during late Pleistocene and Holocene time indicating relative growth of diapirs along the basin margin throughout the most recent geological record.     

AstroGrid: A place for your science

Nicholas A Walton, Silvia Dalla, Eduardo Gonzalez-Solarez, Anita Richards and Jonathan Tedds show off the fast-developing astronomical applications of the UK's virtual observatory service.     

Spectral Diagnostics of an Active Region Observed by the Solar EUV Rocket Telescope and Spectrograph (SERTS)

The EUV spectrum of a solar active region observed by SERTS-89 is used to estimate physical parameters such as electron density, elemental abundance and inhomogeneity in the emitting source. A total of 13 ions, namely, Neiv-vi, Mgv-ix, Sivii-x and Sx, are studied in the SERTS spectral range 170-450 Ú, providing plasma diagnostics at temperatures between10₅ –10⁶ K. Attention is called to results derived from ion pairs of different elements that are formed over similar temperature regimes, which allow special checks on the standard assumptions of spectral analyses. Some EUV lines, not originally reported in the SERTS-89 spectrum, are shown to have measureable intensities and are indicated for future observations.     

Friedmann cosmological models with bulk viscosity in a scale covariant theory

In the presence of perfect fluid with bulk viscosity homogeneous isotropic Friedmann Cosmologies are studied in the scale covariant theory of gravitation. Using special law of variation for Hubble’s parameter, a class of solutions is found. The physical properties of the model are also investigated.     

Drainage ditch erosion history as recorded in the varved sediment of a small lake in East Finland

Short core stratigraphy of total N, P, Zn, Hg and diatoms were investigated in the varved sediment of Lake Heinälampi, a small 8 m deep pond in East Finland. The sediment has recently changed from organic mud to minerogenic silt. The presence of varved sediment offers independent control for ²¹⁰Pb and ¹³⁷Cs dates and these are in good agreement: the sediment quality initially changed around the year 1930 due to increaed field erosion, and the inflow of mineral matter was further increased by ditching of paludified forests in 1980.Diatom analysis reveals that eutrophication has occurred before and concurrent with the sedimentary change. The causes of eutrophication and the increased levels of Zn and Hg are discussed.     

Review: Thermal water resources in carbonate rock aquifers

The current knowledge on thermal water resources in carbonate rock aquifers is presented in this review, which also discusses geochemical processes that create reservoir porosity and different types of utilisations of these resources such as thermal baths, geothermal energy and carbon dioxide (CO₂) sequestration. Carbonate aquifers probably constitute the most important thermal water resources outside of volcanic areas. Several processes contribute to the creation of porosity, summarised under the term hypogenic (or hypogene) speleogenesis, including retrograde calcite solubility, mixing corrosion induced by cross-formational flow, and dissolution by geogenic acids from deep sources. Thermal and mineral waters from karst aquifers supply spas all over the world such as the famous bath in Budapest, Hungary. Geothermal installations use these resources for electricity production, district heating or other purposes, with low CO₂ emissions and land consumption, e.g. Germany’s largest geothermal power plant at Unterhaching near Munich. Regional fault and fracture zones are often the most productive zones, but are sometimes difficult to locate, resulting in a relatively high exploration uncertainty. Geothermal installations in deep carbonate rocks could also be used for CO₂ sequestration (carbonate dissolution would partly neutralise this gas and increase reservoir porosity). The use of geothermal installations to this end should be further investigated.