Four centuries of written documentary sources concerning sea level rise (SLR) in Venice are analysed to complete the study of potential proxies. This literature has been useful to advance knowledge ...in history of science and to recover scientific data. Several case studies have been found and discussed, but only two had complete information to reach quantitative sea level values. The first one was reported by Manfredi (
1732
) and is representative of the 1500–1730 period. The second was by Zendrini (
1821
) who gave a benchmark in 1810. The results are compared with the multiproxy SLR reconstruction for the 1350–2016 period (Camuffo et al.
2017
). Manfredi constitutes an independent verification of this multiproxy series.
The main problems of early wine-spirit thermometers, with special reference to the eighteenth century, are considered with a holistic approach based on historical sources, physical mechanisms, and ...mathematical relationships. Thermometers were hardly comparable and were vulnerable at extreme temperatures, including calibration. Wine-spirit and the vapor pressure exerted at different temperatures, especially in proximity of the boiling points of spirit and water, are analyzed, because they caused the failure of glass tubes. The method suggested by Réaumur of completely removing air from the tube when it was sealed and the opposite one by Micheli du Crest of leaving some air inside are discussed, as well as advantages and disadvantages of using wine-spirit at different mole fractions of ethyl alcohol and water. The original, so-called “true Réaumur” thermometer, its calibration, scale, and response are investigated. The equations that evaluate the deviation from linearity for various factors are derived. Equations are given to convert readings taken with the “true Réaumur” and other early thermometers to Celsius, and at the same time correcting them from the departures due to wine-spirit and the particular calibration. Finally, the direct Celsius scale has been found to be known earlier than believed, in 1740.
Over the centuries, the depths of the most severe storm surges that have flooded Venice have been measured using different reference frames, i.e., related to the algae belt (CM), mean sea level ...(MSL), local land (ZMPS), large-scale leveling (IGM), and satellite altimetry (SA). Some reference frames, i.e., IGM and SA, are absolute, while the others are relative and represent two different physical points of view, i.e., CM and MSL refer to the sea that is rising and ZMPS refers to the land that is subsiding. The perceptions derived from the different systems are contradictory. This paper discusses and compares surges from 1821 to 2021 measured with these frames, also including the commemorative plaques that report the flood depths on walls in Venice. The paper explains the consequences of a change in frame and zero reference, and it transforms the flooding depths from the original systems to make them homogeneous. The severity of flooding changes in terms of rating with the choice of frame. In the 19th century, five storm surges exceeded the famous level of 1966 and, if they were to recur today or in the future, the sea level rise and the local land subsidence that have occurred in the meantime would greatly exacerbate the situation.
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•Taking precise relative humidity measurements even under extreme humidity conditions.•Improving performance of thin film capacitive sensors.•Using warmed-up sensors to precisely ...measure the dew point.•Relative humidity records made through temperature and dew point determinations.
Dampness is one of the worst, and most common problems found in heritage buildings and sites. However, despite its relevance, sensors do not operate satisfactorily in extremely humid environments. The paper analyses the performance of heated capacitive sensors conceived to operate at ambient temperature (T) and very high relative humidity (RH) after having been demisted with short heating. Even if they show better performances than traditional, unheated sensors, they operate at the limit of their range, with severe limitations affecting their time response and accuracy, reducing but not excluding false readings. A method is proposed to combine temperature and relative humidity sensors, and warm-up them in order to reach the best performance interval of the RH sensor, and take measurements in such conditions, i.e. at higher temperature and lower relative humidity. From the combined temperature and relative humidity readings it is possible to calculate the dew point that is invariant to temperature changes. Combining the dew point with an additional measurement of the actual air temperature, it is possible to calculate the actual relative humidity. The use of this method is not necessarily limited to taking more accurate relative humidity readings under extreme dampness, but it may be also applied to improve the quality of readings with sensors that operate in their best performance interval. The same strategy can be used in too dry environments with cooling to raise relative humidity and bring the sensor into the best performance interval.
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•Efficiency of electro-osmosis pumping is better in warm than in cold climate.•Comparison of electro-osmotic intervention can only be made for building under the same climate ...conditions.•How temperature affects the electro-osmosis efficiency.•Suggestions to make better use of electro-osmosis to dry walls or soil.
Electro-osmosis is popularly used as a pump to dry soils or to reduce rising damp in buildings, but the literature results are contradictory. The basic formula of electro-osmosis has been analysed to point out its dependence on temperature, which is masked behind two coefficients, i.e. the dielectric ‘constant’ of water (that is not constant), and the coefficient of dynamic viscosity. These two physical quantities have been calculated with the accurate formulae by Malmberg and Maryott (the dielectric constant) and Voegel (the dynamic viscosity). The electro-osmosis formula includes the ratio between these two coefficients. Although the two formulae that represent them are formulated with equations having a formally different mathematical apparatus, their ratio strictly follows a straight line with values increasing with temperature. Dividing this equation by its initial value (i.e. considered at 0.1 °C) one obtains the Temperature Magnification Factor (TMF) that indicates how much the effectiveness of the system may vary with temperature. TMF is linearly increasing and has been calculated for the whole range of liquid water, i.e. from 0.1 to 99.9 °C. In the interval of the most common wall temperatures, from 0 to 50 °C, TMF increases from 1 to 2.5, showing that in summer, or in warm climate, the efficiency of this method is much higher (e.g. 2.5 times) than in winter or in cold regions. A comparison of the effectiveness of electro-osmotic interventions against rising damp can only be made for buildings under the same climate conditions. This explains the contradictory results found in the literature when case studies from different geographic areas, and different climates, are compared.
After an overview of the problems concerning the early rain-gauges and their thresholds, a study is made to investigate the impact that the instrumental threshold of a rain-gauge has on the ...distribution of precipitation frequency and amount. Tests are performed using two historical datasets, i.e., the observations by Giovanni Poleni in Padua from 1725 to 1760, and Jacopo Bartolomeo Beccari in Bologna from 1723 to 1765, and two modern rain-gauge records, i.e., taken at the Botanical Garden, Padua, and at the Hydrographic, Bologna, from 1990 to 2019. The tests involve applying a filter to the datasets to simulate the action of an instrumental threshold. The result is that the threshold has an enormous impact on the frequency and a smaller one on the total amount. The study includes how the threshold affects the percentile distribution of precipitation amounts. The results provide indications to correct and interpret early records and to test their quality. Moreover, they are useful in the analysis of long time series composed by datasets derived from different instruments for climate studies.
The article offers an overview of the time frames used in instrumental series and how to transform them into modern units. In the early instrumental period, time was measured with sundials or ...mechanical clocks regulated every day with the culmination at noon, making reference to the apparent solar time (AST) and the local meridian. Every day had a slightly different duration, start, and end for the apparent changes of speed of the Sun. When canonical hours were used, hours were computed starting from twilight. In the late eighteenth century, the start was established at midnight. In the mid-nineteenth century, when precise clocks were available, it was possible to adopt an average time, with all days having the same duration, but related to the local meridian. A further step was to unify the time of all cities of a country adopting the time of the capital. Finally, the interregional rails, the telegraph, the telephone, and the international contacts required to unify the different time frames. This lead to the creation of the Coordinated Universal Time (UTC) and the time zones (TZ). The change from AST to UTC introduced two important time differences: one related to the variability of the apparent solar motion and one related to the longitude of the site. Instrumental records, especially the longest ones, are affected by changes in time frames that may cause bias. In this paper, the time changes of 92 selected European cities when they passed from AST to Western European Time, Central Europe Time, or Eastern Europe Time, are considered, and the departures during the calendar year are calculated. Moreover, the bias in temperature derived from the time frame change has also been evaluated in ten case studies over Europe. This paper will assist historians and climatologists to recognize and correct the time departures that affect meteorological series concerning temperature, barometric pressure, and other variables with daily cycles. This correction is crucial to assess climate changes. Specific aims are as follows: to make a friendly explanation of the methodology to pass from old time frames to UTC; to provide transformation equations to remove the bias for the time difference; to pass from time difference to temperature bias to homogenize early records with modern ones.
The earliest temperature series in Paris, from May 1658 to September 1660, taken by Boulliau is made available at daily resolution after a careful work of homogenization, correction and calculation ...of the average values. New results are achieved concerning the Little Florentine Thermometer, building location, thermometer exposure, observation methodologies followed by Boulliau and weather in the mid-seventeenth century. Two methods are used and compared to calculate the daily average from readings taken at random sampling times. The first one is based on the reading needing the smallest correction to be transformed into a daily average; the second considers all the readings of the day and makes a bulk average of the individual results. The series is compared with the temperature record by the Grand Duke Ferdinand II in Florence, which was the primary station of the Medici Network (1654–70). In addition, the comparison of the earliest temperature series in Paris and Florence with their respective 1961–1990 reference period gives a clear image of the change of weather conditions in Europe in the middle of the seventeenth century. Key features were a strong variability for warm-air and cold-air outbreaks, severe winters and cold summers in Paris, not affecting Florence.
This paper deals with the earliest meteorological observations in Florence after the Medici Network (1654–1670), i.e., from mid-seventeenth to mid-eighteenth century, and puts them in the context of ...the history of meteorology in Florence. After the gap caused by the Inquisition, observations started again in the eighteenth century, made by Cipriano Antonino Targioni (1728–1748), Giovanni Targioni-Tozzetti (1737–1740), Pietro Gaetano Grifoni (1751–1766), Leonardo Ximenes (1752), and Luca Martini (1756–1772). The first two records were lost, and this paper considers those by Grifoni and Ximenes. The latter is affected by severe bias; the former is of good quality and has been recovered and analyzed. Both the observers made only one reading a day and the metadata are scarce. The paper discusses several issues: the conversion from the apparent solar time to the Central Europe Time; the transformation from a single reading to a daily average; the identification of the thermometric liquid and the scale; the test made with the snow benchmark; the comparison with the contemporary series in Bologna. The comparison of the reconstructed series with other periods, i.e., 1654–1670, 1881–1910, 1961–1990, and 1991–2017, reveals that in mid-eighteenth century the temperature reached the lowest levels, especially in summer, and showed a sudden warming in the most recent decades.
In the framework of the meteorological observations in Florence after the Medici Network (1654–1670), the earliest surviving record by Pietro Gaetano Grifoni (1751–1766) was followed and partially ...overlapped by the temperature series by Luca Martini (1756–1775), which has been recovered from different sources and analyzed in this paper. Martini series should be divided in two periods, the turning year being 1765, when he changed house, still in Florence. A critical data analysis and the comparison with the Grifoni contemporary series in Florence clarify the thermometric liquid and scale used in the different periods. The reconstruction of the 1756–1775 daily average temperatures is carried out here following a methodology that includes the conversion from the apparent solar time to the Central Europe Time; the transformation from single/double readings to a daily average; the analysis of the hourly temperature variation during the calendar year in the 1961–1990 reference period in Florence; the test made with the snow benchmark; and the correction of the bias due to the local microclimate in the first period. The final series (1751–1775) has been composed combining Grifoni and Martini observations, covers one quarter of the eighteenth century, and constitutes the only surviving outdoor temperature record in Florence. The comparison with other periods from the mid-seventeenth to the early-twenty-first century confirms that in the mid-eighteenth century, the temperature reached the lowest levels and that a marked warming has characterized the most recent decades. Information on the pre-industrial climatology in Florence can be useful for climatic change study.
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