Meteorological Balloons Research Articles

In situ observations of supercooled liquid water clouds over Dome C, Antarctica, by balloon-borne sondes

Abstract. Clouds in Antarctica are key elements that affect radiative forcing and thus Antarctic climate evolution. Although the vast majority of clouds are composed of ice crystals, a non-negligible fraction constitutes supercooled liquid water (SLW; water held in liquid form below 0 °C). Numerical weather prediction models have great difficulty in forecasting SLW clouds over Antarctica, favouring ice at the expense of liquid water and therefore incorrectly estimating the cloud radiative forcing. Remote-sensing observations of SLW clouds have been carried out for several years at Concordia Station (75° S, 123° E; 3233 m above mean sea level), combining active lidar measurements (SLW cloud detection) and passive HAMSTRAD microwave measurements (liquid water path, LWP). The present project aimed at in situ observations of SLW clouds using sondes developed by the company Anasphere, specifically designed for SLW content (SLWC) measurements. These SLWC sondes were coupled to standard meteorological pressure–temperature–humidity sondes from Vaisala and released under meteorological balloons. During the 2021–2022 summer campaign, 15 launches were made, of which 7 were scientifically exploitable above a height of 400 m above ground level, a threshold height imposed by the time the SLWC sonde takes to stabilize after launch. The three main outcomes from our analyses are as follows: (a) the first in situ observations so far of SLW clouds in Antarctica with SLWC sondes; (b) on average, the consistency of SLW cloud heights as observed by in situ sondes and remote-sensing lidar; and (c) the liquid water path (vertically integrated SLWC) deduced by the sondes being generally equal to or greater than the LWP remotely sensed by HAMSTRAD. In general, the SLW clouds were observed in a layer close to saturation (U > 80 %) or saturated (U ∼ 100 %–105 %) just below or at the lowermost part of the entrainment zone, or capping inversion zone, which exists at the top of the planetary boundary layer and is characterized by an inflection point in the potential temperature vertical profile. Our results are consistent with the theoretical view that SLW clouds form and remain at the top of the planetary boundary layer.

UAV Atmosphere Sounding for Rocket Launch Support.

One of the crucial branches of activity at the Łukasiewicz Research Network-Institute of Aviation is developing a suborbital rocket vehicle capable of launching small payloads beyond the Earth's atmosphere, reaching over 100 km in altitude. Ensuring safety is a primary concern, particularly given the finite flight zone and impact area. Crucial to safety analysis is the wind profile, especially in the very first seconds of a flight, when rocket velocity is of the same order as the wind speed. Traditional near-ground wind data sources, ranging from wind towers to numerical models of the atmosphere, have limitations. Wind towers are costly and unfeasible at many test ranges used for launches, while numerical modeling may not reflect the specific ground profile near the launcher due to their large cell size (2 to +10 km). Meteorological balloons are not favorable for such measurements as they aim to provide the launch operator with a wind profile at high altitudes, and are launched only 1-2 times per flight attempt. Our study sought to prototype a wind measurement system designed to acquire near-ground wind profile data. It focuses on measuring wind direction and speed at near-ground altitudes with higher flight frequency, offering data on demand shortly before launch to help ensure safety. This atmosphere sounding system consists of an Unmanned Aerial Vehicle (UAV) equipped with an onboard ultrasonic wind sensor. Some reports in the literature have discussed the possibility of using UAV-borne anemometers, but the topic of measurement errors introduced by placing the anemometer onboard an UAV remains under studied. Limited research in this area underlines the need for experimental validation of design choices-for specific types of UAVs, anemometers, and mounting. This paper presents a literature review, a detailed overview of the prototyped system, and flight test results in both natural (outdoor) and controlled (indoor, no wind) conditions. Data from the UAV system's anemometer was benchmarked against a stationary reference weather station, in order to examine the influence of the UAV's rotor on the anemometer readings. Our findings show a wind speed Root Mean Square Error (RMSE) of 5 m/s and a directional RMSE of below 5.3° (both averaged for 1 min). The results were also compared with similar UAV-based wind measurements. The prototyped system was successfully used in a suborbital rocket launch campaign, thus demonstrating the feasibility of integrating UAVs with dedicated sensors for performing regular meteorological measurements in automatic mode.

Baseline Balloon Stratospheric Aerosol Profiles (B2SAP)—Systematic Measurements of Aerosol Number Density and Size

AbstractStratospheric aerosol plays an important role in Earth's radiative balance. Systematic measurements of stratospheric aerosol number concentration and size are needed to characterize their baseline values and variability, improve understanding of aerosol microphysics, and assess the representation of stratospheric aerosol processes in global models. In situ measurements of particle size distribution provide insight into the responses of stratospheric aerosol processes to perturbations from volcanoes and wildfires, anthropogenic emissions from rockets and aircraft, or intentional injections related to climate intervention. The Baseline Balloon Stratospheric Aerosol Profiles (B2SAP) project uses compact, lightweight payloads carried by meteorological balloons to measure aerosol number density and size distributions, water vapor, ozone, and meteorological data from the surface to the middle stratosphere. The long‐term goal for the B2SAP project is to produce climatologies of aerosol number and size distributions into the middle stratosphere at latitudinally distributed measurement sites. Since March 2019, B2SAP payloads have been launched from Boulder, CO, USA once to twice per month and four to six times per year from Lauder, NZ. These measurements provide a new record of in situ stratospheric aerosol observations and are being used to help validate satellite‐based estimates of stratospheric aerosol size distributions. Here we present 50 vertical profiles from Boulder, CO, from March 2019 to March 2022, to build a NH mid‐latitude climatology of stratospheric aerosol and its variability and investigate the impact of natural perturbations on stratospheric aerosol microphysics.

High moisture confluence in Japan Sea polar air mass convergence zone captured by hourly radiosonde launches from a ship

Some of the heaviest snowfalls in urban areas in the world occur in Japan, particularly in regions that face the Japan Sea. Many heavy snowfalls are produced by a Japan Sea polar air mass convergence zone (JPCZ), which is an atmospheric river-like cloud zone that forms when Siberian cold air flows over the warm Japan Sea. Quantifying how the air–sea interaction strengthens the JPCZ is key to snowfall prediction. However, until our observations with hourly meteorological balloon launches from a training vessel in 2022, no simultaneous air–sea observations targeting the JPCZ had been conducted. Our observations showed that wind direction shifted drastically by about 90 degrees from the surface to an altitude of about 3.5 km within a narrow horizontal range of about 15 km, indicating airflow convergence from the surroundings. Maximum temperature difference between surface air (3 °C) and water was 11 °C near the JPCZ centre with 17 m s−1 wind speed. Large amounts of heat, 718 W m−2, was thus gained from the warm sea. Water vapour was also concentrated by the horizontal convergence, which caused heavy snow, equivalent to 100 cm of snowfall in 7 h. The surrounding sea greatly affects moisture formation within the JPCZ.

Weather observation and forecasting using radiosonde

Weather balloons are high-altitude meteorological balloons particularly used for carrying scientific payloads into the upper atmosphere. These data are obtained by using an instrument called as radiosonde which is attached to the helium filled weather balloon to measure the meteorological data as it ascends up into the atmosphere. For more than 100 years, weather balloons have given valuable information for climate and meteorological research. In this paper, the radiosonde module is designed with negligible risk of failure and cost effectiveness. The instruments to be fixed along with the weather balloon are logging camera, temperature sensor, pressure sensor, humidity sensor, global positioning system (GPS) module and a power source. This module is used to measure and log the basic weather parameters such as pressure, temperature, humidity and this also captures the picture of a particular locality with the help of a microcontroller. This proposed work is useful for observing high altitude weather data which is essential for predicting natural disasters. Further more, it is helpful to analyze the climatological and weather details of a particular region it also plays an important role in estimating agricultural models.

Commercial GNSS Radio Occultation on Aerial Platforms With Off-The-Shelf Receivers

<h3>Abstract</h3> In recent decades, GNSS radio occultation (RO) soundings have proven to be an invaluable input to global weather forecasting. The success of government programs such as COSMIC is now complemented by commercial low-cost cubesats. The result is access to more than 10,000 soundings per day. We examine aerial platforms for commercial GNSS-RO, specifically high-altitude balloons and commercial aviation. Meteorological balloons (radiosondes) are deployed daily in over 900 locations globally. Adding GNSS-RO capability to radiosondes would expand capability and enable local area monitoring. Commercial aviation offers scale with more than 100,000 flights daily. A barrier to entry for the inclusion of GNSS-RO sensors is cost and complexity, as GNSS-RO traditionally requires highly specialized equipment. This paper describes a low-cost and scalable approach to aerial GNSS-RO based on commercial-off-the-shelf (COTS) GNSS receivers. We present hardware prototypes and data processing techniques that demonstrate technical feasibility through the results from several flight testing campaigns.

Astronomical seeing forecast for the Thai National Observatory

Forecasting the astronomical seeing above an observatory can assist astronomers plan their observations. In this study, the astronomical seeing above the Thai National Observatory (TNO) in Doi Inthanon, Chiang Mai, Thailand was simulated using the Weather Research and Forecasting (WRF) model. The model outputs were then compared to Polaris seeing observations and using the Differential Image Motion Monitor (DIMM). Results showed that the forecasts capture the variation of the astronomical seeing fairly well. However, bias correction is needed on the simulations due to lack of data from meteorological balloons to constrain the model.

Reliable model to estimate the profile of the refractive index structure parameter (Cn2) and integrated astroclimatic parameters in the atmosphere.

Based on the statistical study of meteorological balloons equipped with thermosondes, a new model that estimates the profile of the refractive index structure constant (Cn2) is proposed. Utilizing temperature, pressure, and wind shear as inputs, this new approach can estimate vertical profiles of Cn2 with 100 m vertical resolution. We used four outer scale models (Thorpe, HMNSP99, Dewan, and our proposed model) on data acquired from Rongcheng (Shandong Peninsula) and Maoming (Guangdong Province) to estimate the Cn2 profiles and compared the results with the measured Cn2 profile. The proposed method outperformed the other three models, yielding an estimation profile that matched well with the measured median Cn2 profiles, with an average relative error generally less than 3.5% and a mean correlation coefficient larger than 0.72 in Maoming, an average relative error generally less than 3.4% and a mean correlation coefficient larger than 0.84 in Rongcheng. The proposed outer scale model also shows good performance in estimating integrated atmospheric parameters.

Compact and lightweight mid-infrared laser spectrometer for balloon-borne water vapor measurements in the UTLS

Abstract. We describe the development, characterization, and first field deployments of a quantum cascade laser direct absorption spectrometer (QCLAS) for water vapor measurements in the upper troposphere and lower stratosphere (UTLS). The instrument is sufficiently small (30×23×11 cm3) and lightweight (3.9 kg) to be carried by meteorological balloons and used for frequent soundings in the UTLS. The spectrometer is a fully independent system, operating autonomously for the duration of a balloon flight. To achieve the required robustness, while satisfying stringent mass limitations, the concepts for optics and electronics have been fundamentally reconsidered compared to laboratory-based spectrometers. A significant enhancement of the mechanical and optical stability is achieved by integrating a newly designed segmented circular multipass cell which allows for 6 m optical path length in a very compact fashion. The H2O volume mixing ratio is retrieved by calibration-free evaluation of the spectral data, i.e., only relying on SI-traceable measurements and absorption line parameters. The open-path design reduces the risk of contamination and allows for fast response and thus high vertical resolution. Laboratory-based characterization experiments show an agreement within 2 % of reference measurements and a precision of 0.1 % under conditions comparable to the UTLS. The instrument successfully performed two balloon-borne test flights up to 28 km altitude. In the troposphere, the retrieved spectroscopic data show an excellent agreement with the accompanying measurements by a frost point hygrometer (CFH). At higher altitude, the quality of the spectral data remained unchanged, but outgassed water vapor within the instrument enclosure was hindering an accurate measurement of the atmospheric water vapor. Despite this limitation, these test flights demonstrated the operation of a compact laser spectrometer in the UTLS aboard a low-volume meteorological balloon, opening the perspective for future highly resolved, accurate, and cost-efficient soundings.

Projekt nauki wspólnotowej: społeczne monitorowanie skutków katastrofy ekologicznej Deepwater Horizon

The Project of Community Science: Public Monitoring of the Effects of the Deepwater Horizon Ecological Disaster The article discusses the strategies and research methods used within the community science paradigm developed by the Public Lab group. The workshops and practices of scientific cooperation with local communities are discussed on the example of the Public Lab’s founding project – monitoring the effects of an ecological disaster related to the oil spill from BP’s Deepwater Horizon oil platform into the Gulf of Mexico in 2010. The methods used to conduct the research were based on the local community’s involvement and led to the establishment of new models to disseminate data and scientific knowledge in which local participants play a crucial role and have access to essential measurement data. The article discusses the DIY method’s applications, the technique of experimental cartography and mapping performed using meteorological balloons and kites. The community research methods are juxtaposed with the contemporary contexts of the evolving blue turn in the humanities, social sciences, and media practices.

A Comparison of AMPS Forecasts Near the Ross Sea Polynya With Controlled Meteorological Balloon Observations

AbstractThis study presents atmospheric boundary layer observations made over the Ross Sea using a long‐duration Controlled Meteorological (CMET) balloon and a comparison with Antarctic Mesoscale prediction System (AMPS) forecasts. The CMET balloon was launched on 22 November 2017 at 1230 UTC; this flight performed 31 repeated soundings of the atmospheric boundary layer over a period of 70 hr. During the flight the balloon made close passes of the open Terra Nova Bay and Ross Sea polynyas. We use the AMPS forecast during the flight to understand the influence of the polynya on the air sampled by the CMET balloon. Balloon observations of temperature, humidity, and wind velocity generally agree with AMPS forecasts, with the largest disparities in the wind direction field during periods of light wind and when the path of the balloon was near complex topography. To understand the thermodynamic interaction between these polynyas and the atmospheric volume sampled by the balloon, a Lagrangian trajectory model forced by AMPS winds was used to calculate the total and partial derivatives of potential temperature as well as the total water mixing ratio. This allowed us to assess the thermodynamic profile of the overlying atmospheric boundary layer. Based on analysis of the AMPS forecast, we were able to identify a region of warming air with an area of 20,000 km2, centered over the Ross Sea Polynya which was providing a strong heat source at the time of the balloon flight.

Physical Process Cruise 2018

The cruise KH 2018-709 aboard the Research Vessel Kronprins Haakon was the second process cruise of the project the Nansen Legacy. The cruise contributed to task T1-2, on process studies to investigate the atmospheric, oceanographic, radiative and other physical controls on sea ice and stratification, with a general aim to identify and quantify the processes that control the heat budget north of Svalbard and in the Barents Sea. The cruise aimed to deploy oceanographic moorings and gliders, an AUV, a remotely piloted unmanned aircraft, controlled meteorological balloons, collect underway measurements from ship-mounted ocean current profilers, wind profilers, radiometer and wave sensors, and collect ocean stratification, currents, and microstructure profiles along selected transects across the north Spitsbergen shelf and slope. Additionally, wave sensors were deployed at ice floes from ice edge into pack ice. This report provides an overview of the methods employed and the data collected.

Multihour Stratospheric Flights with the Heliotrope Solar Hot-Air Balloon

AbstractStandard meteorological balloons can deliver small scientific payloads to the stratosphere for a few tens of minutes, but achieving multihour level flight in this region is more difficult. We have developed a solar-powered hot-air balloon named the heliotrope that can maintain a nearly constant altitude in the upper troposphere–lower stratosphere as long as the sun is above the horizon. It can accommodate scientific payloads ranging from hundreds of grams to several kilograms. The balloon can achieve float altitudes exceeding 24 km and fly for days in the Arctic summer, although sunset provides a convenient flight termination mechanism at lower latitudes. Two people can build an envelope in about 3.5 h, and the materials cost about $30. The low cost and simplicity of the heliotrope enables a class of missions that is generally out of reach of institutions lacking specialized balloon expertise. Here, we discuss the design history, construction techniques, trajectory characteristics, and flight prediction of the heliotrope balloon. We conclude with a discussion of the physics of solar hot-air balloon flight.

On the estimation of vertical air velocity and detection of atmospheric turbulence from the ascent rate of balloon soundings

Abstract. Vertical ascent rate VB of meteorological balloons is sometimes used for retrieving vertical air velocity W, an important parameter for meteorological applications, but at the cost of crude hypotheses on atmospheric turbulence and without the possibility of formally validating the models from concurrent measurements. From simultaneous radar and unmanned aerial vehicle (UAV) measurements of turbulent kinetic energy dissipation rates ε, we show that VB can be strongly affected by turbulence, even above the convective boundary layer. For “weak” turbulence (here ε≲10−4 m2 s−3), the fluctuations of VB were found to be fully consistent with W fluctuations measured by middle and upper atmosphere (MU) radar, indicating that an estimate of W can indeed be retrieved from VB if the free balloon lift is determined. In contrast, stronger turbulence intensity systematically implies an increase in VB, not associated with an increase in W according to radar data, very likely due to the decrease in the turbulence drag coefficient of the balloon. From the statistical analysis of data gathered from 376 balloons launched every 3 h at Bengkulu (Indonesia), positive VB disturbances, mainly observed in the troposphere, were found to be clearly associated with Ri≲0.25, usually indicative of turbulence, confirming the case studies. The analysis also revealed the superimposition of additional positive and negative disturbances for Ri≲0.25 likely due to Kelvin–Helmholtz waves and large-scale billows. From this experimental evidence, we conclude that the ascent rate of meteorological balloons, with the current performance of radiosondes in terms of altitude accuracy, can potentially be used for the detection of turbulence. The presence of turbulence complicates the estimation of W, and misinterpretations of VB fluctuations can be made if localized turbulence effects are ignored.

Development of instruments for space exploration using meteorological balloons

Indian Centre for Space Physics is engaged in studying terrestrial and extra-terrestrial high energy phenomena from meteorological balloon borne platforms. A complete payload system with such balloons is at the most about five kilograms of weight. One has to adopt innovative and optimal design for various components of the experiment, so that the data can be procured at decent heights of ~ 35-42 km and at the same time, some scientific goals are achieved. In this paper, we mainly describe the instruments in detail and present their test and calibration results. We discuss, how we implemented and tested three major instruments, namely, a Geiger-M\"uller counter, a single crystal scintillator detector and a phoswich type scintillator detector for our missions. We also present some flight data of a few missions to demonstrate the capability of such experiments.

Ultraviolet light measurements (280–400 nm) acquired from stratospheric balloon flight to assess influence on bioaerosols

Viable microorganisms collected from the Earth’s upper atmosphere are mysterious considering the intensely biocidal ultraviolet (UV) light conditions dominating rarefied air. Historically, most investigations examining the relationship between bioaerosols and UV conditions in the upper atmosphere have relied upon model-generated data. To address the shortage of in situ UV measurements in the upper troposphere and lower/middle stratosphere, we flew a meteorological balloon equipped with a UV radiometer and other core environmental sensors. The balloon payload launched from Illinois, USA, on October 6, 2018, and acquired UVA (315–400 nm) + UVB (280–315 nm) measurements for ~ 2 h up to 30.9 km. Above the atmospheric boundary layer, UVA + UVB values registered around 6 mW cm−2, results that were largely consistent with Tropospheric Ultraviolet–Visible model predictions. Performed in a low-cost, reusable manner with commercially available instruments, we show that reliable UV flux data can be acquired with meteorological balloon payload systems. This short communication provides relevant UVA + UVB results for aerobiology and astrobiology studies evaluating the survivability of microorganisms in the upper atmosphere.

Detection of Crab radiation with a meteorological balloon borne phoswich detector

We use existing light weight balloon facility of Indian Centre for Space Physics to detect the X-ray radiation from Crab pulsar with a phoswich detector. We present the design considerations and characterization of the detector used for this purpose. We model the background radiation in the detector environment at various altitudes and use this in spectral analysis. The background radiation level and limitations on the detector allowed us to calculate minimum detection limit for extrasolar radiation sources with our set up.

Looking at “Night-Shining” Clouds from the Stratosphere

One research group studied noctilucent clouds at large distances from a different point of view, using cameras aboard a meteorological balloon that sailed into the stratosphere.

Analysis of airflow around Sapran Nak Airfield using meteorological balloon system and computational fluid dynamics program

This study was conducted to characterize air flow over the study areas through simulation using a commercial computational fluid dynamics (CFD) software, ANSYS Fluent 15.0 and validating them with the actual air measurements using a meteorological balloon system. The study has found that the appropriate setting for upstream aerodynamic surface roughness (z0) was at 0.5 m (90% accuracy) for the sunflower vegetated area and at 0.1 m (85% accuracy) for the area on the mountain covered with small plants and sparse trees. The study, has also demonstrated that the use of CFD and a meteorological balloon system could improve operational parameterizations of z0, suggesting that they are applicable for use to carry out full scale atmosphere-surface simulation models for characterizing air flow over a mountain and nearby areas. Additionally, the use of CFD predicted values were also discussed in identifying unsafe areas for maneuvering helicopters.

Vertical structure of the lower troposphere derived from MU radar, unmanned aerial vehicle, and balloon measurements during ShUREX 2015

The ShUREX (Shigaraki UAV Radar Experiment) 2015 campaign carried out at the Shigaraki Middle and Upper atmosphere (MU) observatory (Japan) in June 2015 provided a unique opportunity to compare vertical profiles of atmospheric parameters estimated from unmanned aerial vehicle (UAV), balloon, and radar data in the lower troposphere. The present work is intended primarily as a demonstration of the potential offered by combination of these three instruments for studying the small-scale structure and dynamics in the lower troposphere. Here, we focus on data collected almost simultaneously by two instrumented UAVs and two meteorological balloons, near the MU radar operated continuously during the campaign. The UAVs flew along helical ascending and descending paths at a nearly constant horizontal distance from the radar (~ 1.0 km), while the balloons launched from the MU radar site drifted up to ~ 3–5 km in the altitude range of comparisons (~ 0.5 to 4.0 km) due to wind advection. Vertical profiles of squared Brünt-Väisälä frequency N2 and squared vertical gradient of generalized potential refractive index M2 were estimated at a vertical resolution of 20 m from pressure, temperature, and humidity data collected by UAVs and radiosondes. Profiles of M2 were also estimated from MU radar echo power at vertical incidence at a vertical sampling of 20 m and various time resolutions (1–4 min). The balloons and the MU radar provided vertical profiles of wind and wind shear S so that two independent estimates of the gradient Richardson number (Ri = N2/S2) could be obtained at a range resolution of 150 m. The two estimates of Ri profiles also showed remarkable agreement at all altitudes. We show that all three instruments detected the same prominent temperature and humidity gradients, down to decameter scales in stratified conditions. These gradients extended horizontally over a few kilometers at least and persisted for hours without significant changes, indicating that the turbulent diffusion was weak. Large discrepancies between N2and M2 profiles derived from the balloon, UAV, and radar data were found in a turbulent layer generated by a Kelvin-Helmholtz (KH) shear flow instability in the height range from 1.80 to 2.15 km. The cause of these discrepancies appears to depend on the stage of the KH billows.