scholarly journals Characterization and Corrections of Relative Humidity Measurement from Meteomodem M10 Radiosondes at Midlatitude Stations

2020 ◽  
Vol 37 (5) ◽  
pp. 857-871
Author(s):  
Jean-Charles Dupont ◽  
Martial Haeffelin ◽  
Jordi Badosa ◽  
Gaelle Clain ◽  
Christophe Raux ◽  
...  
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Humidity Sensor ◽  
Global Climate ◽  
Time Lag ◽  
Capacitive Sensor ◽  
Cold Temperatures ◽  
Humidity Measurements ◽  
Main Effects ◽  
Very High

AbstractMeasurement of water vapor or humidity in the atmosphere is fundamental for many applications. Relative humidity measurements with a capacitive sensor in radiosondes are affected by several factors that need to be assessed and corrected. This work aims to address corrections for the main effects for the Meteomodem M10 radiosonde as a step to meet the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) requirements. The considered corrections are 1) the calibration correction; 2) a slow regime due to the slow diffusion of molecules through the sensor, especially at very high and very low relative humidity conditions; 3) the relative humidity sensor dependence on the gradient of temperature; and 4) the time lag at cold temperatures, which affects measurements in regions of strong relative humidity gradients. These corrections were tested for 26 nighttime and 25 daytime radiosondes in two midlatitude locations for which both Meteomodem M10 and Vaisala RS92 measurements were available. The results show that, after correcting for the four effects, M10 relative humidity measurements are, on average, consistent with the Vaisala RS92 relative humidity values within 2% RH at all altitudes for the nighttime launches (against 6% RH before the correction) and within 5% RH at all altitudes for the daytime launches (against 9% RH before the correction).

Diffusion of water vapor through human skin in hot environment and with application of atropine

1959 ◽  
Vol 14 (2) ◽  
pp. 276-278 ◽  
Author(s):  
Konrad J. K. Buettner ◽  
Frederick F. Holmes
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Human Skin ◽  
Liquid Water ◽  
Water Loss ◽  
Diffusion Resistance ◽  
Vapor Transfer ◽  
Hot Environment ◽  
Human Forearm ◽  
Very High

At room temperatures between 20° and 40°C, vapor transfer through skin of human forearm was tested with four small heated bottles containing air of humidities ranging from 2 to 100% relative humidity. Exposure times ranging from 30 to 120 minutes had no influence on results. Water loss or gain of skin were observed for the different bottles. At very high humidities, liquid water deposit on the skin was measured by weighing a blotter. Skin vapor loss decreases systematically when bottle moisture increases. This increase is enhanced at room temperatures above 24℃, where total loss into a dry bottle increases more than fivefold. This increase seems only partially caused by sweat and partially by a decrease of the skin diffusion resistance. Tourniquet and locally applied atropine did not affect vapor transfer in a cool room. In a hot room, the tourniquet lowered the vapor loss by only 20%, whereas atropine drastically curtailed vapor loss. Submitted on August 25, 1958

Capacitance Humidity Sensor

1995 ◽  
Vol 382 ◽  
Author(s):  
Andrew R.K. Ralston ◽  
Paul E. Thoma ◽  
Carl F. Klein ◽  
Denice D. Denton
Keyword(s):  
Water Vapor ◽  
Chemical Composition ◽  
Relative Humidity ◽  
Humidity Sensor ◽  
Moisture Uptake ◽  
Free Standing ◽  
Sorption Model ◽  
Volume Calculations ◽  
Water Vapor Transmission ◽  
Design Construction

ABSTRACTA capacitance relative humidity (RH) sensor is described that has a design, construction, and material composition that result in an inexpensive and robust sensor. This sensor has a multilayer, free-standing film construction. It consists of a humidity sensitive polyimide (PI) dielectric core and conductive layers consisting of carbon filled polysulfone on each side of the polyirnide film to form a capacitor. The polyimide used is a BPDA-ODA type, and replaces a PMDA-ODA type polyimide used in a previous version of this sensor. The BPDA-ODA sensor has a nominal capacitance of 200 pF and a nominal sensitivity of 13% at 100% RH. The characteristics of this humidity sensor are discussed and compared to the characteristics of the PMDA-ODA type sensor. Characteristics considered include the PI film moisture uptake and water vapor transmission, and the sensors' sensitivity to relative humidity, frequency response, and aging at 85°C/85% RH. The dual-state sorption model and free volume calculations are used to demonstrate that observed differences in the film are due to differences in chemical composition between the films.

scholarly journals Polymer Based Whispering Gallery Mode Humidity Sensor

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2383 ◽  
Author(s):  
Ann Petermann ◽  
Thomas Hildebrandt ◽  
Uwe Morgner ◽  
Bernhard Roth ◽  
Merve Meinhardt-Wollweber
Keyword(s):  
Relative Humidity ◽  
Humidity Sensor ◽  
Real Life ◽  
High Sensitivity ◽  
Whispering Gallery Mode ◽  
Whispering Gallery ◽  
Humidity Measurements ◽  
Wgm Resonators

Whispering gallery mode (WGM) resonators are versatile high sensitivity sensors, but applications regularly suffer from elaborate and expensive manufacturing and read-out. We have realized a simple and inexpensive concept for an all-polymer WGM sensor. Here, we evaluate its performance for relative humidity measurements demonstrating a sensitivity of 47 pm/% RH. Our results show the sensor concepts’ promising potential for use in real-life applications and environments.

Multimodel Analysis of the Water Vapor Feedback in the Tropical Upper Troposphere

2006 ◽  
Vol 19 (20) ◽  
pp. 5455-5464 ◽  
Author(s):  
Ken Minschwaner ◽  
Andrew E. Dessler ◽  
Parnchai Sawaengphokhai
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Sea Surface ◽  
Specific Humidity ◽  
Upper Troposphere ◽  
The Mean ◽  
Tropical Upper Troposphere

Abstract Relationships between the mean humidity in the tropical upper troposphere and tropical sea surface temperatures in 17 coupled ocean–atmosphere global climate models were investigated. This analysis builds on a prior study of humidity and surface temperature measurements that suggested an overall positive climate feedback by water vapor in the tropical upper troposphere whereby the mean specific humidity increases with warmer sea surface temperature (SST). The model results for present-day simulations show a large range in mean humidity, mean air temperature, and mean SST, but they consistently show increases in upper-tropospheric specific humidity with warmer SST. The model average increase in water vapor at 250 mb with convective mean SST is 44 ppmv K−1, with a standard deviation of 14 ppmv K−1. Furthermore, the implied feedback in the models is not as strong as would be the case if relative humidity remained constant in the upper troposphere. The model mean decrease in relative humidity is −2.3% ± 1.0% K−1 at 250 mb, whereas observations indicate decreases of −4.8% ± 1.7% K−1 near 215 mb. These two values agree within the respective ranges of uncertainty, indicating that current global climate models are simulating the observed behavior of water vapor in the tropical upper troposphere with reasonable accuracy.

scholarly journals Anomalous holiday precipitation over southern China

2018 ◽  
Vol 18 (22) ◽  
pp. 16775-16791 ◽  
Author(s):  
Jiahui Zhang ◽  
Dao-Yi Gong ◽  
Rui Mao ◽  
Jing Yang ◽  
Ziyin Zhang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Cloud Cover ◽  
Southern China ◽  
Eastern China ◽  
Time Lag ◽  
Precipitation Amount ◽  
Specific Humidity ◽  
Middle Troposphere ◽  
The Mean

Abstract. The Chinese Spring Festival (CSF, also known as the Chinese New Year or Lunar New Year) is the most important festival in China. Lunar New Year's Day (LNYD) is the first day of the Lunar New Year. Traditionally, the CSF holiday begins a couple of days before LNYD and ends on lantern day, lasting for approximately 2 weeks. In this paper, based on the long-term station observations from 1979 to 2012, the precipitation during the holiday over southern China (108–123° E and 21–33° N, 155 stations) tends to be lower than that before and after the holiday. The mean precipitation frequency anomaly from the fourth day to the sixth day after LNYD (i.e., days [+4, +6]) decreases by −7.4 %. Simultaneously, the daily precipitation amount experiences a reduction of −0.62 mm day−1 during days [+2, +5]. The holiday precipitation anomalies are strongly linked to the anomalies of relative humidity (ΔRH) and cloud cover. The station observations of the ΔRH show an evident decrease from day +2 to day +7, and a minimum appears on days [+4, +6], with a mean of −3.9 %. The ΔRH vertical profile displays significant drying below approximately 800 hPa. Between 800 and 1000 hPa, the mean ΔRH is −3.9 %. The observed station daytime low cloud cover (LCC) evidently decreases by −6.1 % during days [+4, +6]. Meanwhile, the ERA-Interim daily LCC also shows a comparable reduction of −5.0 %. The anomalous relative humidity is mainly caused by the decreased water vapor in the lower-middle troposphere. Evident negative specific humidity anomalies persist from day −3 to day +7 in the station observations. The average specific humidity anomaly for days [+4, +6] is −0.73 g kg−1. When the precipitation days are excluded, the anomaly remains significant at −0.46 g kg−1. A significant water vapor deficit is observed in the lower troposphere below 700 hPa. Between 800 and 1000 hPa, the mean specific humidity drops by −0.70 g kg−1. This drier lower-middle troposphere is due to anomalous northerly winds, which are closely related to the cyclonic circulation anomaly over the northwestern Pacific. The time-lag correlation demonstrates that approximately 1 week after a lower temperature occurs over eastern China, a stronger cyclone is observed over the western Pacific. The possible mechanism needs further clarification through elaborate observation and numerical modeling.

Intercomparisons of Stratospheric Water Vapor Sensors: FLASH-B and NOAA/CMDL Frost-Point Hygrometer

2007 ◽  
Vol 24 (6) ◽  
pp. 941-952 ◽  
Author(s):  
H. Vömel ◽  
V. Yushkov ◽  
S. Khaykin ◽  
L. Korshunov ◽  
E. Kyrö ◽  
...  
Keyword(s):  
Water Vapor ◽  
Global Climate ◽  
Time Lag ◽  
The Arctic ◽  
Mean Deviation ◽  
Upper Troposphere ◽  
Stratospheric Water Vapor ◽  
Frost Point ◽  
Dry Conditions ◽  
Monitoring And Diagnostics

Studies of global climate rely critically on accurate water vapor measurements. In this paper, a comparison of the NOAA/Climate Monitoring and Diagnostics Laboratory (CMDL) frost-point hygrometer and the Fluorescent Advanced Stratospheric Hygrometer for Balloon (FLASH-B) Lyman-alpha hygrometer is reported. Both instruments were part of a small balloon payload that was launched multiple times at Sodankylä, Finland. The comparison shows agreement well within the instrumental uncertainties between both sensors in the Arctic stratospheric vortex. The mean deviation between both instruments in the range between 15 and 25 km is −2.4% ± 3.1% (one standard deviation). The comparison identified some instrumental issues, such as a low mirror-temperature calibration correction for the NOAA/CMDL frost-point hygrometer as well as a time lag. It was found that the FLASH-B hygrometer measures water vapor reliably above 7 km in the polar atmosphere. Comparisons in the upper troposphere are affected by the gain change of the NOAA/CMDL hygrometer, causing a lag and a wet bias in the tropospheric low gain setting under the dry conditions in the upper troposphere.

scholarly journals Comparison of the GRUAN data products for Meisei RS-11G and Vaisala RS92-SGP radiosondes at Tateno (36.06° N, 140.13° E), Japan

2019 ◽  
Author(s):  
Eriko Kobayashi ◽  
Shunsuke Hoshino ◽  
Masami Iwabuchi ◽  
Takuji Sugidachi ◽  
Kensaku Shimizu ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Global Climate ◽  
Japan Meteorological Agency ◽  
Radiosonde Data ◽  
Night Time ◽  
Sensor Orientation ◽  
Data Products ◽  
Humidity Measurements ◽  
The Difference ◽  
Humidity Dependence

Abstract. A total of 87 dual flights of Meisei RS-11G radiosondes and Vaisala RS92-SGP radiosondes were carried out at the Aerological Observatory of the Japan Meteorological Agency (36.06° N, 140.13° E, 25.2 m) from April 2015 to June 2017. Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) data products from both sets of radiosonde data for 52 flights were subsequently created using a documented processing program along with the provision of optimal estimates for measurement uncertainty. The authors then quantified differences in the performance of the radiosondes using GRUAN data products. The temperature measurements of RS-11G were 0.4 K lower than those of RS92-SGP in the stratosphere during daytime observation. The relative humidity measurements of RS-11G were 2‰RH lower than those of RS92-SGP under 90–100‰RH conditions, while RS-11G gave 5‰RH higher values than RS92-SGP under ≤ 50‰RH conditions. The results from a dual flight of RS-11G and a cryogenic frostpoint hygrometer (CFH) also showed that RS-11G gave 1–10‰RH higher values than the CFH in the troposphere. The authors additionally investigated the RS-11G minus RS92-SGP difference of temperature and relative humidity based on combined uncertainties to clarify major influences behind the difference. It was found that temperature differences in the stratosphere during daytime observation were within the range of uncertainty (k = 2), and that sensor orientation is the major source of uncertainty in RS92-SGP temperature measurement, while sensor albedo is the major source for RS-11G. The relative humidity difference in the troposphere was larger than the uncertainty (k = 2) after the radiosondes had passed through the cloud layer, and temperature-humidity dependence correction was the major source of uncertainty in RS-11G relative humidity measurement. Uncertainties for all soundings were also statistically investigated. Most night-time temperature differences for pressures of > 10 hPa were in agreement, while relative humidity differences in the middle troposphere exhibited significant differences. Around half of all daytime temperature differences at pressures of ≤ 150 hPa and relative humidity differences around the 500 hPa level were not in agreement.

scholarly journals Humidity observations in the Arctic troposphere over Ny-Ålesund, Svalbard based on 14 years of radiosonde data

2007 ◽  
Vol 7 (1) ◽  
pp. 1261-1293 ◽  
Author(s):  
R. Treffeisen ◽  
R. Krejci ◽  
J. Ström ◽  
A. C. Engvall ◽  
A. Herber ◽  
...  
Keyword(s):  
Relative Humidity ◽  
The Arctic ◽  
Radiosonde Data ◽  
Cold Temperatures ◽  
Radiative Balance ◽  
Seasonal Behaviour ◽  
Humidity Measurements ◽  
Characteristic Features ◽  
Frequency Occurrence ◽  
Humidity Profiles

Abstract. Water vapour is an important component in the radiative balance of the polar atmosphere. We present a study covering fourteen-years of data of tropopsheric humidity profiles measured with standard radiosondes at Ny-Ålesund (78°55' N 11°52' E) during the period from 1991 to 2005. It is well known that relative humidity measurements are less reliable at cold temperatures when measured with standard radiosondes. The data were corrected for errors and used to determine key characteristic features of the vertical and temporal RH evolution in the Arctic troposphere over Ny-Ålesund. We present frequency occurrence of ice-supersaturation layers in the troposphere, their vertical span, temperature and statistical distribution. Supersaturation with respect to ice shows a clear seasonal behaviour. In winter (October–February) it occurred in 22% of all cases and less frequently in spring (March–May 13%), and summer (June–September, 10%). The results are finally compared with findings from the SAGE II satellite instrument on subvisible clouds.

scholarly journals Comparisons of temperature, pressure and humidity measurements by balloon-borne radiosondes and frost point hygrometers during MOHAVE 2009

2011 ◽  
Vol 4 (4) ◽  
pp. 4357-4401 ◽  
Author(s):  
D. F. Hurst ◽  
E. G. Hall ◽  
A. F. Jordan ◽  
L. M. Miloshevich ◽  
D. N. Whiteman ◽  
...  
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Mixing Ratios ◽  
Frost Point ◽  
Humidity Measurements ◽  
Large Measurement ◽  
Measurement Uncertainties ◽  
Temperature And Pressure ◽  
Measurement Biases

Abstract. We compare coincident, balloon-borne, in situ measurements of temperature and pressure by two radiosondes (Vaisala RS92, Intermet iMet-1-RSB) and measurements of relative humidity (RH) by Vaisala RS92 sondes and frost point hygrometers. Data from a total of 28 balloon flights with mixed payloads are analyzed in 1-km altitude bins to quantify measurement biases between sensors and how they vary with altitude. The disparities between sensors determined here are compared to measurement uncertainties quoted by the two radiosonde manufacturers. Our comparisons expose several flight profiles with anomalously large measurement differences. Excluding these anomalous profiles, 33 % of RS92-iMet median temperature differences exceed the uncertainty limits calculated from manufacturer-quoted uncertainties. A statistically significant, altitude-independent bias of about 0.5 ± 0.2 °C is revealed for the RS92-iMet temperature differences. Similarly, 23 % of RS92-iMet median pressure differences exceed the quoted uncertainty limits, with 83 % of these excessive differences above 16 km altitude. The pressure differences are altitude dependent, increasing from −0.6 ± 0.9 hPa at the surface to 0.7 ± 0.1 hPa above 15 km. Temperature and pressure differences between redundant RS92 sondes on the same balloon exceed manufacturer-quoted reproducibility limits 20 % and 2 % of the time, respectively, with most of the excessive differences belonging to anomalous difference profiles. Relative humidity measurements by RS92 sondes are compared to other RS92 sondes and to RH values calculated using frost point hygrometer measurements and coincident radiosonde temperature measurements. For some flights the RH differences are anomalously large, but in general are within the ±5 % RH measurement uncertainty limits quoted for the RS92. The quantitative effects of RS92 and iMet pressure and temperature differences on frost point-based water vapor mixing ratios and RH values, respectively, are also presented.

scholarly journals Comparison of the GRUAN data products for Meisei RS-11G and Vaisala RS92-SGP radiosondes at Tateno (36.06° N, 140.13° E), Japan

2019 ◽  
Vol 12 (6) ◽  
pp. 3039-3065 ◽  
Author(s):  
Eriko Kobayashi ◽  
Shunsuke Hoshino ◽  
Masami Iwabuchi ◽  
Takuji Sugidachi ◽  
Kensaku Shimizu ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Global Climate ◽  
Temperature Measurements ◽  
Japan Meteorological Agency ◽  
Radiosonde Data ◽  
Sensor Orientation ◽  
Processing Program ◽  
Data Products ◽  
Humidity Measurements ◽  
Humidity Dependence

Abstract. A total of 87 dual flights of Meisei RS-11G radiosondes and Vaisala RS92-SGP radiosondes were carried out at the Aerological Observatory of the Japan Meteorological Agency (36.06∘ N, 140.13∘ E, 25.2 m) from April 2015 to June 2017. Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) data products from both sets of radiosonde data for 52 flights were subsequently created using a documented processing program along with the provision of optimal estimates for measurement uncertainty. Differences in the performance of the radiosondes were then quantified using the GRUAN data products. The temperature measurements of RS-11G were, on average, 0.4 K lower than those of RS92-SGP in the stratosphere for daytime observations. The relative humidity measurements of RS-11G were, on average, 2 % RH (relative humidity) lower than those of RS92-SGP under 90 % RH–100 % RH conditions, while RS-11G gave on average 5 % RH higher values than RS92-SGP under ≤50 % RH conditions. The results from a dual flight of RS-11G and a cryogenic frost point hygrometer (CFH) also showed that RS-11G gave 1 % RH–10 % RH higher values than the CFH in the troposphere. Differences between the RS-11G and RS92-SGP temperature and relative humidity measurements, based on combined uncertainties, were also investigated to clarify major influences behind the differences. It was found that temperature differences in the stratosphere during daytime observation were within the range of uncertainty (k=2), and that sensor orientation is the major source of uncertainty in the RS92-SGP temperature measurement, while sensor albedo is the major source of uncertainty for RS-11G. The relative humidity difference in the troposphere was larger than the uncertainty (k=2) after the radiosondes had passed through the cloud layer, and the temperature–humidity dependence correction was the major source of uncertainty in RS-11G relative humidity measurement. Uncertainties for all soundings were also statistically investigated. Most nighttime temperature measurements for pressures of >10 hPa were in agreement, while relative humidity in the middle troposphere exhibited significant differences. Around half of all daytime temperature measurements at pressures of ≤150 hPa and relative humidity measurements around the 500 hPa level were not in agreement.

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