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Dario Camuffo 《Climatic change》2002,53(1-3):297-329
Calibration and instrumental errors of early thermometers are analysed. The first concepts, the development of scientific ideas, the main problems linked to the construction of early thermometers and the calibration are considered in order to evaluate errors. The operating principle of the `constant-volume' air thermometer is presented andits limits are discussed. The theory shows that for an ideal Amontons' thermometer, only one calibration point is sufficient from which the other can be calculated; it is therefore possible to determine the difference from an ideal instrument. A comparison is made between calibrations and instruments made by G. Amontons (1699), G. Poleni (Venice, 1709; Padova 1725), and J.H. Lambert (1779). Amontons' thermometer needs to be integrated with a barometric reading; an important error arises from the different density of mercury during calibration and usage. The calibration was made in winter and at the upper point the thermometer was at 100 ° C, while the barometer remained near 0 ° C. However, field observations were made with both instruments at the same temperature and this caused an error that in the cold season is negligible, but in the hot season reaches 1 ° C. Problems connected with the calibration and scale linearity are discussed in view of the beliefs of the time and the operative methodologies used in early meteorology. Emphasis is given to comparability of different instruments, thermometric scales and calibration methodologies used in Padova in the 18th century for Amontons' Poleni's, Fahrenheit's, Réaumur's and Delisle's thermometers. The instrument supports and the incision of the scale were subject to expand or contract depending on temperature or humidity changes, and this was a source of error that can be corrected with the help of observed or estimated data. Problems linked to the construction of thermometers have been evaluated, as well as the linearity of displacements of the thermometric liquid, or the drift due to ageing and transformation of the thermometric liquid, the glass or the support. All these errors have been evaluated and some of them have been found negligible, but some are of the order of 0.5 ° C. The quantitative resultsobtained here can also be usefully applied to correct and validate other long series. 相似文献
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Quantitative Evaluation of Water Deposited By Dew on Monuments 总被引：1，自引：0，他引：1
Samples of White and Green Carrara marble, and three types oflimestone and brick exposed in the field vertically and horizontally were used to evaluate condensationon monuments during clear sky nights. Experiments in a simulation chamber under controlledconditions led to a general equation for the actual amount of water deposited on a surface by dew.This is determined by: How much and for how long the surface temperature falls below the dew point,the moisture content in the air and the ventilation. On clear nights, the condensation on buildingstructures facing the sky may reach some 0.2 kg m-2 (or 0.2 mm), whereas condensation on verticalsurfaces is very small. Computation of the seasonal trend of night-time condensationshowed that the maximum amount of water condensed per night occurs in the autumn, with the moreabundant concentration of moisture in the air. The total amount of water condensed per month isfound to be a maximum in the summer-autumn period. Morning condensationfor the thermal inertia of monuments is also relevant, and has been calculated to reach the same order of magnitude as thenocturnal dew. A detailed analysis of the temperature and mixing ratio profiles near a condensingsurface has shown two different situations. In still air, the two profiles follow an exponentiallaw and the thermal and the concentration layers lie within a few tens of millimetres. Inthe presence of turbulence, the thickness of these two layers is dramatically reduced. In still air, infront of a vertical, chilly surface, the deposition rate of air pollutants by thermophoresis and/orStefan flow is increased by 3 or 4 times in comparison with a horizontal surface. In the presence ofturbulence, the thickness of the thermal and concentration layers was dramatically reduced, makingthese two kinds of deposition much faster. 相似文献
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D. Camuffo 《Boundary-Layer Meteorology》1982,22(2):233-240
The dynamics of the nocturnal IBL over a small hilly island on the Mediterranean Sea are discussed, particularly for clear nights characterized by light wind, when typically a nocturnal inversion may grow. Among different cases, two typical situations are observed, depending on the steadiness of the wind. In the first case the inversion alternatively grows and is eroded from aloft until it is destroyed; in the second, it grows with half the speed usual at inland sites and its height is bounded by the top of the hill. The Stüve diagrams show that the warm sea surface can supply the energy required to lift airborne pollutants over the CCL. 相似文献
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A short history of the series with daily observations of barometric pressure in Padova (since 1725) is made, with special reference to the types of barometers used, their locations, the types of corrections (which were only partial in the early period), the calibrations and the comparison with primary instruments. The paper also describes the homogenisation of the series and the procedures used to fill the small gaps. The Padova series was compared with previously well investigated series from the ADVICE and IMPROVE projects and especially with the nearby Milan series in order to check its reliability. Trend analysis shows an increase in pressure (some 1 hPa) during the last a hundred year. This trend is a common feature for Northern Italy. An effect of the increased air pressure is a local lowering of the Northern Mediterranean Sea level by 1 cm. The part of the year mostly affected by this increase is from late spring to August and corresponds to an extension of the hot season, characterised by an earlier start, and longer duration of the Azores Anticyclone. This reduces the penetration of the Atlantic disturbances in the Northern Mediterranean and the precipitation associated with the passage of fronts. This change is associated with an increase in thermoconvective activity with thunderstorms and heavy precipitation. This explains why, in the last decades, the annual total amount of precipitation is slightly decreased and at the same time the frequency of intense rainfall is increased. Moreover, a comparison of the day-to-day pressure variability with the Western Mediterranean Oscillation (WeMO) indicates a significant positive correlation during the late autumn-early winter period. An increase of the WeMO index means a strengthening of the baric dipole from Azores to Northern Italy, that could be explained by a deepening of the cyclonic circulation over northern Italy from November to January. 相似文献
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The local sea-breeze circulation in Venice is found to have typical characteristics but the nocturnal flow is found to be
quite complex. This latter results is due to unequal cooling of the Alps and adjacent low-lying regions. The horizontal and
vertical structure of the flow has been investigated using data obtained from surface anemometers and pilot balloon observations.
Results show that the circulation is about 500 m in depth and achieves a maximum speed of 6 m s−1. 相似文献
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The local sea-breeze circulation in Venice is found to have typical characteristics but the nocturnal flow is found to be quite complex. This latter result is due to unequal cooling of the Alps and adjacent low-lying regions. The horizontal and vertical structure of the flow has been investigated using data obtained from surface anemometers and pilot balloon observations. Results show that the circulation is about 500 m in depth and achieves a maximum speed of 6 m s–1 相似文献
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This paper presents the earliest temperature observations, scheduled every 3–4 h in the 1654–1670 period, which have been
recovered and analysed for the first time. The observations belong to the Medici Network, the first international network
of meteorological observations, based on eleven stations, the two main ones being Florence and Vallombrosa, Italy. All observations
were made with identical thermometers and operational methodology, including outdoor exposure in the shade and in the sunshine
to evaluate solar heating, state of the sky, wind direction and precipitation frequency. This paper will consider only the
regular temperature series taken in the shade. The observations were made with the newly invented spirit-in-glass thermometer,
also known as Little Florentine Thermometer (LFT). The readings have been transformed into modern units of temperature (°C)
and time (TMEC). The LFT has been analysed in detail: how it was made, its linearity, calibration and performances. Since
the middle of the LIA, the climate in Florence has shown less than 0.18°C warming. However, although the yearly average showed
little change, the seasonal departures are greater, i.e. warmer summers, colder winters and unstable mid seasons. The temperature
in the Vallombrosa mountain station, 1,000 m a.m.s.l, apparently rose more, i.e. 1.41°C. A discussion is made on the interpretation
of this finding: how much it is affected by climate change or bias. A continuous swinging of the temperature was observed
in the Mediterranean area, as documented by the long instrumental observations over the 1654–2009 period. However, changes
in vegetation, or exposure bias might have contributed to reduce the homogeneity of the series over the centuries. 相似文献
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Dario Camuffo C. Bertolin N. Diodato M. Barriendos F. Dominguez-Castro C. Cocheo A. della Valle E. Garnier M. -J. Alcoforado 《Climatic change》2010,100(1):137-142
The paper discusses the newly produced temperature and precipitation series from instrumental observations in the Western
Mediterranean (WM) area, dating back to 1654. The two series had a continuous swing and unstable coupling passing from correlation
to anti-correlation. Only after 1950 are they permanently anti-correlated with increasing temperature and decreasing precipitation.
It is not clear how long this coupling will persist. The analysis of the correlation between the Northern Hemisphere (NH)
and the WM temperature anomalies and their trends shows a certain variability from 1850 to 1950; later a strong coupling between
NH and WM. Results suggest that the WM climate is approaching a turning point that might locally oppose the adverse effects
of Global Warming. 相似文献