A methodology for study of in-service drift of meteorological humidity sensors

Bell, S A; Carroll, P; Beardmore, S L; England, Chelsi; Mander, N

doi:10.1088/1681-7575/aa6dd0

Cited by 10 publications

(4 citation statements)

References 14 publications

(18 reference statements)

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“…The declared accuracy of the sensors decreases when the 90% RH is exceeded, and the uncertainty increases with the humidity level. When saturation is reached and the capacitive film is damp, the sensor is faulty and three solutions are possible, depending on the manufacturer: (i) the sensor, by default, indicates 100%, and this is the most common use; (ii) the sensor continues to operate, giving levels above 100%; (iii) the output is stopped because it is unreliable [6,25,26]. After the sensor is wet, and in contact with liquid water, it takes a long time to evaporate the sorbed moisture, and its output is not reliable until the polymer film dries.…”

Section: Glass Temperature and Mistingmentioning

confidence: 99%

Preventing Glass Misting in Indoor Showcases with Burial Remains at Al Ain, UAE

Camuffo,

Giorio,

della Valle

et al. 2024

Heritage

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The historic house of Sheikh Mohammed Bin Khalifa, Al Ain (Abu Dhabi, UAE) belongs to the World Heritage Cultural Sites. The courtyard and two rooms include mudbrick archaeological remains that are preserved in showcases for public display. The building lies in a hot desert climate and needs air conditioning to be comfortable. This paper is concerned with indoor showcases and their compatibility with the indoor climate. Sometimes, misting for condensation is generated on the glass panes for the temperature and humidity contrast between the room climate and the showcases that are embedded in the floor. When misting occurs, the remains cannot be viewed. This paper investigates indoor glass misting, the exchanges of heat and moisture between archaeological remains, showcases and rooms, and the results after a year of environmental monitoring. An aim is to assess the potential risks for the preservation of the remains, recognizing the frequency and severity of the conditions for condensation. Another aim is to discuss mitigation methodologies to avoid glass misting, e.g., (i) reducing the room cooling; (ii) raising the glass pane temperature with electrical devices; (iii) increasing air exchanges between showcases and rooms; (iv) adopting a combination of these methodologies.

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Section: Glass Temperature and Mistingmentioning

confidence: 99%

Preventing Glass Misting in Indoor Showcases with Burial Remains at Al Ain, UAE

Camuffo,

Giorio,

della Valle

et al. 2024

Heritage

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“…Temperature sensors and, more in general, sensors that have been exposed for prolonged periods of time to harsh environmental conditions, are known to exhibit slight modifications in their physical properties that can change also their measurements -or drift (Bell et al 2017;Musacchio et al 2015). This drift is often evaluable as few hundredths of a °C (Kowal et al 2020), comparable with the signal coming from climate change-related thermal phenomena, like the permafrost thawing (Biskaborn et al 2019;Haberkorn et al 2021).…”

Section: On-site Sensors Calibration Activities (2018 and 2020)mentioning

confidence: 99%

Metrological approach for permafrost temperature measurements

Coppa,

Sanna,

Paro

et al. 2024

Preprint

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Permafrost degradation is a growing direct impact of climate change. Detecting permafrost reductions, in terms of its extension, deepening of the active layer and rise of the base is fundamental to capture the magnitude of trends and address actions and warnings. Temperature profiles in permafrost allow direct understanding of the status of the frozen ground layer and its evolution in time. The Sommeiller Pass permafrost monitoring station, at about 3000 m of elevation, is the key site of the regional network installed in 2009 during the European Project “PermaNET” in the Piedmont Alps (NW Italy). The station consists of three vertical boreholes 5, 10 and 100 m deep with different characteristics, equipped with thermometric chains for a total of 36 temperature sensors (thermistors type). The raw collected data shows an active layer 8-9 m thick, and a degradation of the base at approximately 60 m of depth since 2014, corresponding to about 0.03 °C/yr. In order to verify and better quantify this potential degradation, three on-site sensor calibrations campaigns were carried out aimed to understand the reliability of the measurements in progress. By repeated calibrations, two key results have been achieved: the profiles have been corrected for biases and the re-calibration allowed to distinguish the effective change of permafrost temperatures along the years, from possible drifts of the sensors, which can be of the same order of magnitude of the investigated thermal change. The reduction of permafrost starting from 2012 at a depth of ~60 m has been confirmed, with a rate of 0.042 ± 0.005 °C/yr. This paper reports the implementation and installation of the on-site metrology laboratory, the dedicated calibration procedure adopted, the calibration results and the resulting adjusted data, profiles and their evolution in time. It is intended as a further contribution to the ongoing studies and definition of best practices, to improve data traceability and comparability, as prescribed by the World Meteorological Organization Global Cryosphere Watch programme.

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“…Relative humidity (RH) is an important thermodynamic quantity in various branches of science and technology, such as meteorology, climatology, air-conditioning, wood drying and ceramics industries, that is subject to advancing metrology [1][2][3][4][5][6][7][8]. However, conventional RH is not uniformly defined, and the definitions available typically do not cover the full range of potential applicability [9,10].…”

Section: Introductionmentioning

confidence: 99%

Defining relative humidity in terms of water activity: III. Relations to dew-point and frost-point temperatures

Feistel¹,

Hellmuth²,

Lovell-Smith³

2022

Metrologia

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Relative humidity (RH) is a fundamental quantity used in many fields of engineering and science, in particular also in meteorology and climate research. Relative fugacity (RF) and, equivalently, relative activity of water vapour in humid air have recently been proposed as a physically well-founded, unambiguous common metrological reference quantity for several conventional but mutually inconsistent definitions of RH. The RF definition is valid also beyond perfect-gas conditions and above boiling and sublimation temperatures. While differences between RH and RF mostly remain within uncertainties of typical present-day RH measurements, such systematic discrepancies are expected to be of substantial climatological relevance. Consequently, interdisciplinary harmonisation of RH definitions is overdue within the SI framework. Dew-point and frost-point temperatures are preferred measurands in humidity metrology using, for example, chilled-mirror hygrometers. Here, relations are presented for estimating RF from those temperatures, based on equations of state of the 2011 IUGG standard TEOS-10, the “International Thermodynamic Equation of Seawater – 2010”. Recommendations are given for numerically computing RF using the open-source TEOS-10 SIA Library . The asymptotic limiting laws of RF for nearly saturated humid air exhibit the familiar form of Clausius-Clapeyron-like equations, despite refraining from ideal-gas assumptions. Under various practical conditions, these simple equations may cover even the full humidity range with only minor residuals compared to the full numerical TEOS-10 solution for RF.

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A methodology for study of in-service drift of meteorological humidity sensors

Cited by 10 publications

References 14 publications

Preventing Glass Misting in Indoor Showcases with Burial Remains at Al Ain, UAE

Preventing Glass Misting in Indoor Showcases with Burial Remains at Al Ain, UAE

Metrological approach for permafrost temperature measurements

Defining relative humidity in terms of water activity: III. Relations to dew-point and frost-point temperatures

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