The statistic and analysis of atmospheric ducts worldwide using radiosonde data

2016 ◽  
Author(s):  
Xiaojing Hao ◽  
Lixin Guo ◽  
Leke Lin ◽  
Qingliang Li ◽  
Yusheng Zhang
Keyword(s):  
Radiosonde Data ◽  
Atmospheric Ducts

scholarly journals Enhanced Neural Network Model for Worldwide Estimation of Weighted Mean Temperature

2021 ◽  
Vol 13 (12) ◽  
pp. 2405
Author(s):  
Fengyang Long ◽  
Chengfa Gao ◽  
Yuxiang Yan ◽  
Jinling Wang
Keyword(s):  
Neural Network ◽  
Real Time ◽  
Model Performance ◽  
Global Scale ◽  
Radiosonde Data ◽  
Model Parameters ◽  
Measured Temperature ◽  
Weighted Mean ◽  
Weighted Mean Temperature ◽  
Application Scope

Precise modeling of weighted mean temperature (Tm) is critical for realizing real-time conversion from zenith wet delay (ZWD) to precipitation water vapor (PWV) in Global Navigation Satellite System (GNSS) meteorology applications. The empirical Tm models developed by neural network techniques have been proved to have better performances on the global scale; they also have fewer model parameters and are thus easy to operate. This paper aims to further deepen the research of Tm modeling with the neural network, and expand the application scope of Tm models and provide global users with more solutions for the real-time acquisition of Tm. An enhanced neural network Tm model (ENNTm) has been developed with the radiosonde data distributed globally. Compared with other empirical models, the ENNTm has some advanced features in both model design and model performance, Firstly, the data for modeling cover the whole troposphere rather than just near the Earth’s surface; secondly, the ensemble learning was employed to weaken the impact of sample disturbance on model performance and elaborate data preprocessing, including up-sampling and down-sampling, which was adopted to achieve better model performance on the global scale; furthermore, the ENNTm was designed to meet the requirements of three different application conditions by providing three sets of model parameters, i.e., Tm estimating without measured meteorological elements, Tm estimating with only measured temperature and Tm estimating with both measured temperature and water vapor pressure. The validation work is carried out by using the radiosonde data of global distribution, and results show that the ENNTm has better performance compared with other competing models from different perspectives under the same application conditions, the proposed model expanded the application scope of Tm estimation and provided the global users with more choices in the applications of real-time GNSS-PWV retrival.

Evaluation of daily and diurnal signals of total precipitable water (TPW) over the Indian Ocean based on TMI retrieved 3-day composite estimates and radiosonde data

2007 ◽  
Vol 27 (6) ◽  
pp. 761-770 ◽  
Author(s):  
V. Sajith ◽  
Jimmy O. Adegoke ◽  
Santosh K. Raghavan ◽  
H. S. Ram Mohan ◽  
Vinod Kumar ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
Total Precipitable Water ◽  
The Indian Ocean

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 Interannual variability of precipitable water

1996 ◽  
Vol 14 (4) ◽  
pp. 464-467 ◽  
Author(s):  
R. P. Kane
Keyword(s):  
Interannual Variability ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
High Latitudes ◽  
Zonal Winds ◽  
Low Latitudes ◽  
Linear Trends

Abstract. The 12-month running means of the surface-to-500 mb precipitable water obtained from analysis of radiosonde data at seven selected locations showed three types of variability viz: (1) quasi-biennial oscillations; these were different in nature at different latitudes and also different from the QBO of the stratospheric tropical zonal winds; (2) decadal effects; these were prominent at middle and high latitudes and (3) linear trends; these were prominent at low latitudes, up trends in the Northern Hemisphere and downtrends in the Southern Hemisphere.

Dependence of Aerosol Particle Concentration in Surface Air over the Moscow Region on Wind Speed and Lapse Rate

2021 ◽  
pp. 103-110
Author(s):  
E. A. Stulov ◽  
◽  
E. V. Sosnikova ◽  
N. A. Monakhova ◽  
◽  
...  
Keyword(s):  
Surface Layer ◽  
Wind Speed ◽  
Particle Concentration ◽  
Meteorological Factors ◽  
Lapse Rate ◽  
Radiosonde Data ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Simple Estimation ◽  
The City

Based on the daily measurements of atmospheric aerosol characteristics in the city of Dolgoprudny (20 km from the center of Moscow) carried out during 2013-2018, the influence of some meteorological factors on the concentration of various aerosol fractions in the surface layer of the atmosphere is analyzed. It is that the aerosol concentration depends most on the wind speed and the vertical temperature gradient. The method of simple estimation of aerosol particles accumulation conditions in the surface layer based on the use of standard radiosonde data is developed.

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 Spatial and seasonal variability of medium- and high-frequency gravity waves in the lower atmosphere revealed by US radiosonde data

2014 ◽  
Vol 32 (9) ◽  
pp. 1129-1143 ◽  
Author(s):  
S. D. Zhang ◽  
C. M. Huang ◽  
K. M. Huang ◽  
F. Yi ◽  
Y. H. Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
Gravity Waves ◽  
Seasonal Variability ◽  
High Frequency ◽  
Lower Atmosphere ◽  
Radiosonde Data ◽  
High Latitudes ◽  
Middle Latitudes ◽  
Momentum Fluxes ◽  
Horizontal Momentum

Abstract. We extended the broad spectral method proposed by Zhang et al. (2013) for the extraction of medium- and high-frequency gravity waves (MHGWs). This method was applied to 11 years (1998–2008) of radiosonde data from 92 stations in the Northern Hemisphere to investigate latitudinal, continuous vertical and seasonal variability of MHGW parameters in the lower atmosphere (2–25 km). The latitudinal and vertical distributions of the wave energy density and horizontal momentum fluxes as well as their seasonal variations exhibit considerable consistency with those of inertial gravity waves. Despite the consistency, the MHGWs have much larger energy density, horizontal momentum fluxes and wave force, indicating the more important role of MHGWs in energy and momentum transportation and acceleration of the background. For the observed MHGWs, the vertical wavelengths are usually larger than 8 km; the horizontal wavelengths peak in the middle troposphere at middle–high latitudes. These characteristics are obviously different from inertial gravity waves. The energy density and horizontal momentum fluxes have similar latitude-dependent seasonality: both of them are dominated by a semiannual variation at low latitudes and an annual variation at middle latitudes; however at high latitudes, they often exhibit more than two peaks per year in the troposphere. Compared with the inertial GWs, the derived intrinsic frequencies are more sensitive to the spatiotemporal variation of the buoyancy frequency, and at all latitudinal regions they are higher in summer. The wavelengths have a weaker seasonal variation; an evident annual cycle can be observed only at middle latitudes.

scholarly journals Characteristics of mid-latitude planetary waves in the lower atmosphere derived from radiosonde data

2012 ◽  
Vol 30 (10) ◽  
pp. 1463-1477 ◽  
Author(s):  
R. Wang ◽  
S. D. Zhang ◽  
H. G. Yang ◽  
K. M. Huang
Keyword(s):  
Standing Wave ◽  
Zonal Wind ◽  
Lower Stratosphere ◽  
Radiosonde Data ◽  
Wind Component ◽  
Jet Stream ◽  
Fort Worth ◽  
Vertical Wavelength ◽  
Subtropical Jet Stream ◽  
Subtropical Jet

Abstract. The activities of mid-latitude planetary waves (PWs) in the troposphere and lower stratosphere (TLS) are presented by using the radiosonde data from 2000 to 2004 over four American stations (Miramar Nas, 32.9° N, 117.2° W; Santa Teresa, 31.9° N, 106.7° W; Fort Worth, 32.8° N, 97.3° W; and Birmingham, 33.1° N, 86.7° W) and one Chinese station (Wuhan, 30.5° N, 114.4° E). Statistically, strong PWs mainly appear around subtropical jet stream in the troposphere and lower stratosphere. In the troposphere, the activities of the mid-latitude PWs are strong around the centre of the subtropical jet stream in winter and become small near the tropopause, which indicates that the subtropical jet stream may strengthen the propagation of PWs or even be one of the PW excitation sources. Among the three disturbance components of temperature, zonal and meridional winds, PWs at Wuhan are stronger in the temperature component, but weaker in the zonal wind component than at the other four American stations. While in the meridional wind component, the strengths of PW spectral amplitudes at the four American stations decrease from west to east, and their amplitudes are all larger than that of Wuhan. However, the PWs are much weaker in the stratosphere and only the lower frequency parts remain. The amplitudes of the PWs in the stratosphere increase with height and are strong in winter with the zonal wind component being the strongest. Using the refractive index, we found that whether the PWs could propagate upward to the stratosphere depends on the thickness of the tropopause reflection layer. In the case study of the 2000/2001 winter, it is observed that the quasi 16-day wave in the troposphere is a quasi standing wave in the vertical direction and propagates upward slowly with vertical wavelength greater than 24 km in the meridional component. It propagates eastward with the zonal numbers between 5 and 8, and the quasi 16-day wave at Wuhan is probably the same quasi 16-day wave at the three American stations (Miramar Nas, Santa Teresa and Fort Worth), which propagates steadily along the latitude. The quasi 16-day wave in the stratosphere is also a standing wave with vertical wavelength larger than 10 km in the zonal wind component, and it is westward with the zonal number 1–2. However, the quasi 16-day wave in the stratosphere may not come from the troposphere because of the different concurrent times, propagation directions and velocities. By using the global dataset of NCEP/NCAR reanalysis data, the zonal propagation parameters of 16-day waves in the troposphere and stratosphere are calculated. It is found that the tropospheric 16-day wave propagates eastward with the zonal number 6, while the stratospheric 16-day wave propagates westward with the zonal number 2, which matches well with the results of radiosonde data.

scholarly journals Estimation of atmospheric mixing layer height from radiosonde data

2014 ◽  
Vol 7 (6) ◽  
pp. 1701-1709 ◽  
Author(s):  
X. Y. Wang ◽  
K. C. Wang
Keyword(s):  
North America ◽  
Potential Temperature ◽  
Mixing Layer ◽  
Specific Humidity ◽  
Radiosonde Data ◽  
Consistent Estimate ◽  
Climate Data ◽  
Layer Height ◽  
Temperature And Humidity ◽  
Mixing Layer Height

Abstract. Mixing layer height (h) is an important parameter for understanding the transport process in the troposphere, air pollution, weather and climate change. Many methods have been proposed to determine h by identifying the turning point of the radiosonde profile. However, substantial differences have been observed in the existing methods (e.g. the potential temperature (θ), relative humidity (RH), specific humidity (q) and atmospheric refractivity (N) methods). These differences are associated with the inconsistency of the temperature and humidity profiles in a boundary layer that is not well mixed, the changing measurability of the specific humidity and refractivity with height, the measurement error of humidity instruments within clouds, and the general existence of clouds. This study proposes a method to integrate the information of temperature, humidity and cloud to generate a consistent estimate of h. We apply this method to high vertical resolution (~ 30 m) radiosonde data that were collected at 79 stations over North America during the period from 1998 to 2008. The data are obtained from the Stratospheric Processes and their Role in Climate Data Center (SPARC). The results show good agreement with those from N method as the information of temperature and humidity contained in N; however, cloud effects that are included in our method increased the reliability of our estimated h. From 1988 to 2008, the climatological h over North America was 1675 ± 303 m with a strong east–west gradient: higher values (generally greater than 1800 m) occurred over the Midwest US, and lower values (usually less than 1400 m) occurred over Alaska and the US West Coast.

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