Meteorological Temperature Profiler Research Articles

Microphysical Characterization of Boundary Layer Ice Particles: Results from a 3-Year Measurement Campaign in Interior Alaska

Abstract A three-winter study has been conducted to better understand the relationship between atmospheric conditions and ice fog or diamond dust microphysics. Measurements were conducted east of downtown Fairbanks in interior Alaska during nonprecipitating conditions. Atmospheric conditions were measured with several weather stations around the Fairbanks region and two meteorological temperature profiler instruments (ATTEX MTP-5HE and MTP-5PE). Near-surface ice particle microphysical observations were conducted with the Particle Phase Discriminator mark 2, Karlsruhe edition (PPD-2K), instrument, which measures particles from 8 to 112 μm (sphere equivalent). Panoramic camera images were captured and saved every 10 min throughout the campaign for visual assessment of atmospheric conditions. Machine learning was used to classify both cloud particle microphysical characteristics from the PPD-2K data and to categorize boundary layer conditions using the panoramic camera images. For panoramic camera images, data were categorized as cloudy, clear, fog, snowing, and a nearby power plant plume. For the PPD-2K machine learning study, the scattering pattern images were used to identify rough surface, pristine, sublimating, and spherical particles. Three additional categories were used to identify indeterminant or saturated images. These categories and categories derived from weather station data (e.g., temperature ranges) are used to quantify ice microphysical properties under different conditions. For the complete microphysical dataset, pristine plates or columns accounted for 15.5%, 16.3% appeared to be sublimating particles, and 43.4% were complex particles with either rough surfaces or multiple branches. Although the temperature was as warm as −20°C during measurements, only 1.3% of the particles were classified as liquid. Significance Statement Boundary layer ice particles are frequently present in the near-surface atmosphere when surface temperatures drop below −20°C. Substantial human impacts can occur due to visibility degradation and deposition of particles on surfaces. Understanding particle shape, size, and phase (liquid or solid) is important for understanding those impacts. This study presents the results of a 3-yr measurement campaign in Fairbanks, Alaska, in which we relate ice particle characteristics to lower atmospheric conditions. Results should improve weather forecasting and hazard prediction.

Meteorological multi-rotor unmanned aerial complex and its application for monitoring of the atmosphere

A design of a meteorological complex based on multi-rotor aeromobile platforms of unmanned aerial vehicles and its possible application for measuring vertical profiles of the main meteorological parameters of the atmosphere, including the air temperature, humidity, and pressure are considered. An example of a comparison of multicopter measurements with the data obtained using an MPT-5 meteorological temperature profiler is given.

Urban-Scale Computational Fluid Dynamics Simulations with Boundary Conditions from Similarity Theory and a Mesoscale Model

Mesoscale numerical weather prediction models usually provide information regarding environmental parameters near urban areas at a spatial resolution of the order of thousands or hundreds of meters, at best. If detailed information is required at the building scale, an urban-scale model is necessary. Proper definition of the boundary conditions for the urban-scale simulation is very demanding in terms of its compatibility with environmental conditions and numerical modeling. Here, steady-state computational fluid dynamics (CFD) microscale simulations of the wind and thermal environment are performed over an urban area of Kozani, Greece, using both the k-ε and k-ω SST turbulence models. For the boundary conditions, instead of interpolating vertical profiles from the mesoscale solution, which is obtained with the atmospheric pollution model (TAPM), a novel approach is proposed, relying on previously developed analytic expressions, based on the Monin Obuhkov similarity theory, and one-way coupling with minimal information from mesoscale indices (Vy = 10 m, Ty = 100 m, L*). The extra computational cost is negligible compared to direct interpolation from mesoscale data, and the methodology provides design phase flexibility, allowing for the representation of discrete urban-scale atmospheric conditions, as defined by the mesoscale indices. The results compared favorably with the common interpolation practice and with the following measurements obtained for the current study: SODAR for vertical profiles of wind speed and a meteorological temperature profiler for temperature. The significance of including the effects of diverse atmospheric conditions is manifested in the microscale simulations, through significant variations (~30%) in the critical building-related design parameters, such as the surface pressure distributions and local wind patterns.

The experience of remote temperature-water content sounding of atmosphere during drift of R/V “Akademik Tryoshnikov”

For the first time experience was gained with the operation of Russian equipment for water content and temperature remote sensing of the lower atmosphere in the Arctic. The comparison the results of measurements by radiometric systems with data of radiosoundings in wide range of meteorological conditions had been executed. It is shown that mean difference between integral atmospheric water content, measured by water vapor radiometer WVR, and calculated from radiosoundings data does not exceed 6 % with standard deviation 0.54 kg/m2 and significant correlation coefficient 0,92. Analysis the data of meteorological temperature profiler MTR-5 allows to conclude that in general its adequately reproduce air temperature profiles in the atmospheric lower 1000 m layer. Some deviations take place only in cases of large temperature gradients. Preliminary analysis of WVR data showed that monthly mean value of integral atmospheric water content in area under study in April 2019 year practically coincides with calculated from radiosoundings, performed in 1983—1988 years at the polar station Barentsburg, nearest to the drift region, 3.61 and 3.62 kg/m2 respectively. Same time hourly mean values of integral atmospheric water content during drift varied from 2 to 10 kg/m2, with extreme values recorded between April 15 and April 20, probably due to intensive transport of air masses of the Atlantic origin. Based on MTR-5 data it was concluded that despite differences in sounding technology, the place and time of observations, the statistics of inversions registered during drift correspond well to statistics of inversions, recorded on the Arctic coastal stations and over sea ice cover of the Weddell Sea in winter.

Temperature inversion and mixing height: critical indicators for air pollution in hot arid climate

Boundary layer temperature inversion and mixing heights are important parameters in understanding the atmospheric dispersion of air pollution. Surface and elevated inversions were analyzed within the planetary boundary layer over Kuwait, a coastal urban city situated in a typical hot, arid climate. Temperature inversions constitute a natural hazard by trapping smog emitted from pollution sources. Temperature inversions were measured by the Meteorological Temperature Profiler version (MTP-5H) using a scanning microwave radiometer over the course of a complete year (2013). Remote continuous measurements (4 min interval) of temperature profiles were collected (total readings = 130,986). Daytime and nocturnal temperature inversion variations were presented. The effects of five atmospheric parameters, namely ambient temperature, relative humidity, wind speed, solar radiation, and precipitation on the surface and elevated inversion, were presented. In general, there was a significant correlation between surface and elevated inversions with four meteorological parameters (p value ≤ .01). Results show a weak correlation between the inversions analyzed by MTP-5H and the MH modeled by the WRF.

Validation of a method for the remote determination of potential aircraft icing spatial zones

Aircraft icing remains an urgent problem of today. One of the promising means of passive temperature remote sensing in the lower (1-kilometer layer) atmosphere is a meteorological temperature profiler called MTP-5. This paper presents the results obtained by a method of remote determination of potential aircraft icing spatial zones and its validation by the example of two International Airports, Novosibirsk and Tomsk. For Tomsk, one year was analyzed (October 2012-September 2013) and for Novosibirsk, one month, January 2015. The atmosphere remote sensing method is the measurement of air temperature in the lower atmosphere layer using the meteorological temperature profiler (MTP-5) to determine the potential aircraft icing zones during landing or take-off to ensure high-quality analysis. The method, combined with the Schultz and Politovich method, shows a result similar to that obtained with the Godske method. Estimation of the icing forecasting accuracy for the two methods shows that the Schultz and Politovich method has higher accuracy than the Godske method on the data used for the two airports.

Estimates of the Refractive Index and Regular Refraction of Optical Waves in the Atmospheric Boundary Layer: Part 1, Refractive Index

The possibility of estimating the optical refractive index in the atmospheric boundary layer from air temperature profiles measured with a MTP-5 meteorological temperature profiler is studied. The refractive index profiles retrieved from MTP-5 data and from aerological measurements are compared. Examples of the refractive index and its derivatives for different seasons are given.

Estimates of the Refractive Index and Regular Refraction of Optical Waves in the Atmospheric Boundary Layer: Part 2, Laser Beam Refraction

Possible displacements of laser beams in the atmospheric boundary layer under the effect of regular refraction are calculated. The case where a radiation source is located at the level of underlying surface is considered. The displacements are estimated for different wavelengths and angles of the beam entrance into the atmosphere. The calculations are based on experimental data on the optical refractive index up to an altitude of 1000 m received in long-term (1 year) measurements of the vertical air temperature profiles with a MTP-5 meteorological temperature profiler.

Application of MTP-5PE meteorological temperature profiler in an airport for determining spatial zones of possible aircraft Icing

We present the results of applying the MTP-5PE meteorological temperature profiler for determining the spatial zones of possible aircraft icing in Tomsk airport on March 17, 2013. The spatial zones were determined using the RAP-algorithm, the Godske formula, as well as the AMIS-RF data for retrieving the humidity profile. The RAP algorithm and the Godske formula are shown to predict similar locations of spatial zones of possible aircraft icing. However, the RAP results are closer to the actual icing reports available from aircraft crews.

Применение метеорологического температурного профилемера MTP-5PЕ в аэропорту для определения пространственных зон возможного обледенения воздушного судна

Применение метеорологического температурного профилемера MTP-5PЕ в аэропорту для определения пространственных зон возможного обледенения воздушного судна

Measurement-calculation complex for monitoring and forecasting meteorological situations at airports

We describe the measurement and calculation complex for monitoring and forecasting the meteorological situation at airports, which comprises MTP-5PE meteorological temperature profiler, WXT520 Vaisala Weather Transmitter, main and remote terminals for managing the complex, network data storage, two high-resolution meteorological models, server, and SKIF Cyberia cluster at Tomsk State University. The paper presents the results of monitoring and forecasting the atmospheric temperature profile and surface wind speed and direction, pressure, humidity, and temperature for the previous winter, when different extreme weather events were observed in Bogashevo airport. It is shown that the measured and calculated vertical temperature profiles in the lower part of the atmospheric boundary layer show high level of qualitative and quantitative agreement of results.

The analysis of results of remote sensing monitoring of the temperature profile in lower atmosphere in Bergen (Norway)

Considered is the application of MTP-5 meteorological temperature profiler used for the remote sensing of vertical profiles of the air temperature in the planetary boundary layer and the lower one-kilometer layer of the atmosphere. The measurements were carried out in Bergen (Norway) in 2011–2012. The obtained dataset of temperature profiles has temporal resolution of five minutes and vertical resolution of 50 m. The MTP-5 data are complemented with the measurements of the air temperature and the wind taken at two automatic weather stations and with the measurements of the rain intensity made with the rain radar. Studied is the impact of meteorological conditions and precipitation on the MTP-5 readings. It is revealed that formation of a thin water film (of ice or, to a smaller degree, of sleet) on the surface of the sensor cover of MTP-5 has a significant impact on the data of the temperature monitoring. The removal of intensive precipitation (the precipitation rate is >0.2 mm/hour) improved the reliability and quality of the temperature profile monitoring. In particular, it is demonstrated that significant air pollution and stably stratified atmospheric conditions which lead to low temperatures are reliably monitored with this instrument.

Study of parameters of the atmospheric boundary layer under urban conditions by means of local and remote diagnostics. Part 1. Interlevel wind speed correlations

The results of complex measurements of meteorological parameters at two observation sites in Moscow with a Volna-4 sodar, Meteo-2 ultrasonic meteorological station, and MTP-5 meteorological temperature profiler are considered. The coefficients of the interlevel wind speed correlation are analyzed after initial data averaging over 10-min time intervals. A minimum of correlation is identified, which corresponds to the height of the urban roughness sublayer. The possibility of determining the height of the atmospheric surface layer over urbanized territory from estimates of the coefficients of correlation is discussed. It is noted that an increase in the wind speed results in a growth of the interlevel correlation inside the urban roughness sublayer and above the atmospheric surface layer; however, the correlation changes insignificantly in the inertial sublayer.

Study of the atmospheric boundary layer parameters under urban conditions with local and remote diagnostics facilities. Part. 2. Air temperature and heat flux

We considered the results of the complex measurements of meteorological parameters at two observation sites in Moscow with the help of Volna-4 sodar, the Meteo-2 ultrasonic meteorological station, and the MTP-5 meteorological temperature profiler. The frequency of occurrence and the heights of temperature inversion boundaries under the conditions of woodland-park zone are analyzed. The obtained results are compared with analogous estimates of some other authors for the central part of the city. It is found that a stable stratification of the urban roughness sublayer takes place considerably more often in the woodland-park zone of the city than in the central part of the urbanized territory.

Height of the internal mixing layer as determined from Volna sodar data

A comparative analysis of the heights of the internal mixing layer estimated from sodar data and from vertical-temporal temperature profiles measured by an MTP-5 meteorological temperature profiler has been performed. The internal mixing layer is defined as a layer of intense turbulent pulsations. The comparison has shown that Volna sodars are capable of recording the vertical-temporal behavior of the area of intense turbulent heat exchange with the underlying surface to the fullest degree. An algorithm is proposed for an automatic procedure of determining the height of the internal mixing layer for Volna sodars. The seasonal dynamics of the internal mixing layer for several years has been analyzed.