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 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.

scholarly journals Tropospheric water vapour and relative humidity profiles from lidar and microwave radiometry

2014 ◽  
Vol 7 (5) ◽  
pp. 1201-1211 ◽  
Author(s):  
F. Navas-Guzmán ◽  
J. Fernández-Gálvez ◽  
M. J. Granados-Muñoz ◽  
J. L. Guerrero-Rascado ◽  
J. A. Bravo-Aranda ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Microwave Radiometer ◽  
Radiosonde Data ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Night Time ◽  
New Approach ◽  
Lidar Measurements ◽  
Humidity Profiles

Abstract. In this paper, we outline an iterative method to calibrate the water vapour mixing ratio profiles retrieved from Raman lidar measurements. Simultaneous and co-located radiosonde data are used for this purpose and the calibration results obtained during a radiosonde campaign in summer and autumn 2011 are presented. The water vapour profiles measured during night-time by the Raman lidar and radiosondes are compared and the differences between the methodologies are discussed. Then, a new approach to obtain relative humidity profiles by combination of simultaneous profiles of temperature (retrieved from a microwave radiometer) and water vapour mixing ratio (from a Raman lidar) is addressed. In the last part of this work, a statistical analysis of water vapour mixing ratio and relative humidity profiles obtained during 1 year of simultaneous measurements is presented.

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).

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 Índices termodinâmicos durante a campanha GOAmazon2014/5 e comparação com dados da reanálise ERA-Interim

2020 ◽  
Vol 42 ◽  
pp. e19
Author(s):  
Matheus Tolentino da Silva ◽  
Henrique De Melo Jorge Barbosa ◽  
Theotonio Mendes Pauliquevis Júnior
Keyword(s):  
Relative Humidity ◽  
Dry Season ◽  
Amazon Rainforest ◽  
Cloud Formation ◽  
Radiosonde Data ◽  
Radiative Balance ◽  
Thermodynamic Conditions ◽  
The Difference ◽  
Seasonal Analysis ◽  
Humidity Profiles

The thermodynamic indexes LCL, LFC, CINE and CAPE characterize atmospheric instability, and allow the study of cloud formation and convection, important phenomena for the hydrologic cycle and the radiative balance. For this reason, this work makes a seasonal analysis of these thermodynamic indexes computed from radiosondes released during the GOAmazon2014/5 experiment. A comparison was made with ERA-Interim reanalysis for both these indexes and the temperature and relative humidity profiles. Analysis of radiosonde data shows that the median vertical profile of relative humidity in the dry season was lower in 2015 when compared to 2014, resulting in higher LCL (~50 hPa at 18 Z) and lower CAPE (~50% lower). The difference stems from a more severe dry season in 2015 when compared with 2014. The comparison with the reanalysis reveals that modeled LCL values are only compatible with observed ones at 18 Z (mean bias -10 hPa). On the other hand, CAPE values are always incompatible (mean bias -750 j/kg). Results indicate that ERA Interim poorly represents the thermodynamic conditions over the Amazon rainforest.

scholarly journals Comparison of microwave satellite humidity data and radiosonde profiles: a survey of European stations

2005 ◽  
Vol 5 (2) ◽  
pp. 1529-1550 ◽  
Author(s):  
V. O. John ◽  
S. A. Buehler
Keyword(s):  
Systematic Difference ◽  
Radiosonde Data ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Comparison Results ◽  
Microwave Sounding Unit ◽  
Humidity Measurements ◽  
Upper Tropospheric Humidity ◽  
Microwave Sounding ◽  
The Difference

Abstract. A method to compare upper tropospheric humidity (UTH) from satellite and radiosonde data has been applied to the European radiosonde stations. The method uses microwave data as a benchmark for monitoring the performance of the stations. The present study utilizes three years (2002–2003) of data from channel 18 (183.31±1.00 GHz) of the Advanced Microwave Sounding Unit-B (AMSU-B) aboard the satellites NOAA-15 and NOAA-16. The comparison is done in the radiance space, the radiosonde data were transformed to the channel radiances using a radiative transfer model. The comparison results confirm that there is a dry bias in the UTH measured by the radiosondes. This bias is highly variable among the stations and the years. This variability is attributed mainly to the differences in the radiosonde humidity measurements. The results also hint at a systematic difference between the two satellites, the channel 18 brightness temperature of NOAA-15 is on average 1.0 K higher than that of NOAA-16. The difference of 1 K corresponds to approximately 7% relative error in UTH which is significant for climatological applications.

scholarly journals Humidity observations in the Arctic troposphere over Ny-Ålesund, Svalbard based on 15 years of radiosonde data

2007 ◽  
Vol 7 (10) ◽  
pp. 2721-2732 ◽  
Author(s):  
R. Treffeisen ◽  
R. Krejci ◽  
J. Ström ◽  
A. C. Engvall ◽  
A. Herber ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Low Temperatures ◽  
The Arctic ◽  
Radiosonde Data ◽  
Radiative Balance ◽  
Seasonal Behaviour ◽  
Humidity Measurements ◽  
Characteristic Features ◽  
Humidity Profiles

Abstract. Water vapour is an important component in the radiative balance of the polar atmosphere. We present a study covering fifteen years of data of tropospheric humidity profiles measured with standard radiosondes at Ny-Ålesund (78°55' N 11°52' E) during the period from 1991 to 2006. It is well-known that relative humidity measurements are less reliable at low temperatures when measured with standard radiosondes. The data was corrected for errors and used to determine key characteristic features of the vertical and temporal relative humidity evolution in the Arctic troposphere over Ny-Ålesund. We present frequencies of 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 19% of all cases and less frequently in spring (March–May 12%), and summer (June–September, 9%). Finally, the results are compared with findings from the SAGE II satellite instrument on subvisible clouds.

scholarly journals Vertical air motions derived from a descending radiosonde using a lightweight hard ball as the parachute

2013 ◽  
Vol 6 (5) ◽  
pp. 8107-8127 ◽  
Author(s):  
H. Chen ◽  
Y. Zhu ◽  
J. Zhang ◽  
Y. Xuan
Keyword(s):  
Northern China ◽  
Lower Atmosphere ◽  
Radiosonde Data ◽  
Small Magnitude ◽  
Abstract Knowledge ◽  
Launch Site ◽  
Wind Profiler Radar ◽  
Vertical Wind Speed ◽  
The Difference ◽  
Hard Ball

Abstract. Knowledge of vertical air motions in the atmosphere is important for meteorological and climate studies due to its impact on clouds, precipitation and the vertical transport of air masses, heat, momentum, and composition. It is among the most difficult quantities to measure because of its small magnitude. In this study, a descending radiosonde technique has been developed to detect the vertical wind speed (VW) in the atmosphere. The system is composed of a radiosonde and a 0.5-m diameter hard ball made of plastic foam that acts as a parachute. The radiosonde hangs under the hard ball by a string which is then cut when the instrument is elevated into the upper troposphere by a balloon. The VW is derived from the difference between the observed radiosonde descent rate and the calculated radiosonde descent rate in still air based on fluid dynamics. Deduction of the appropriate drag coefficient for the radiosonde is facilitated by the symmetrical shape of the parachute. An intensive radiosonde launch experiment was held in northern China during the summer seasons of 2010 to 2012. This study uses radiosonde data collected during the campaign to retrieve the vertical air velocity within the radiosonde altitude-detecting range. In general, the VW ranges from −1 to 1 m s−1. Strong vertical air motion (~2 m s−1) is seen in a few radiosonde measurements. Although considerable uncertainties exist in measuring weak vertical air motions, a case study shows that there is reasonable agreement between retrievals of VW in the lower atmosphere from the radiosonde and a wind profiler radar located at the launch site.

scholarly journals Characteristics of Size Change of Tropical Cyclones Traversing the Philippines

2018 ◽  
Vol 146 (9) ◽  
pp. 2891-2911 ◽  
Author(s):  
Shu-Jeng Lin ◽  
Kun-Hsuan Chou
Keyword(s):  
Angular Momentum ◽  
Relative Humidity ◽  
Tropical Cyclones ◽  
Momentum Flux ◽  
Vertical Wind Shear ◽  
The Philippines ◽  
Sea Surface ◽  
Japan Meteorological Agency ◽  
The South ◽  
Size Change

Abstract This study investigates the size changes of tropical cyclones (TCs) traversing the Philippines based on a 37-yr statistical analysis. TC size is defined by the radius of 30-kt (≈15.4 m s−1) wind speed (R30) from the best track data of the Japan Meteorological Agency. A total of 71 TCs passed the Philippines during 1979–2015. The numbers of size increase (SI; 36) and size decrease (SD; 34) cases are very similar; however, the last 15 years have seen more SI cases (17) than SD cases (11). SI and SD cases mostly occur along northerly and southerly paths, respectively, after TCs pass the Philippines. Before landfall, SI cases have small initial sizes and weak intensities, but SD cases have larger initial sizes and stronger intensities. After landfall, most SI cases are intensifying storms, and most SD cases are nonintensifying storms. Composite analyses of vertical wind shear, absolute angular momentum flux, relative humidity, and sea surface temperature between SI and SD cases are compared. All of these values are larger in SI cases than in SD cases. Furthermore, the interdecadal difference in the ratio of the numbers of SI to SD cases reveals an unusually high number of SI cases during 2001–15. The synoptic patterns between 1979–2000 and 2001–15 are analyzed. The high SI ratio in the latter period is related to strong southwesterly wind in the south of the South China Sea that raised relative humidity, warmed the sea surface, and increased import of angular momentum flux.

Sign in / Sign up

Export Citation Format

Share Document