Articles | Volume 15, issue 22
https://doi.org/10.5194/amt-15-6545-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/amt-15-6545-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
17 Nov 2022
Research article |
| 17 Nov 2022
A comparative evaluation of snowflake particle shape estimation techniques used by the Precipitation Imaging Package (PIP), Multi-Angle Snowflake Camera (MASC), and Two-Dimensional Video Disdrometer (2DVD)
Charles Nelson Helms
CORRESPONDING AUTHOR
Mesoscale Atmospheric Processes Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
NASA Postdoctoral Program – Oak Ridge Associated Universities, Oak Ridge, TN, USA
Earth System Science Interdisciplinary Center, University of Maryland, College Park, College Park, MD, USA
Stephen Joseph Munchak
Mesoscale Atmospheric Processes Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
Ali Tokay
Mesoscale Atmospheric Processes Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
Claire Pettersen
Climate and Space Sciences and Engineering Department, University of Michigan, Ann Arbor, MI, USA
Related authors
S. Joseph Munchak, Robert S. Schrom, Charles N. Helms, and Ali Tokay
Atmos. Meas. Tech., 15, 1439–1464, https://doi.org/10.5194/amt-15-1439-2022, https://doi.org/10.5194/amt-15-1439-2022, 2022
Short summary
Short summary
The ability to measure snowfall with weather radar has greatly advanced with the development of techniques that utilize dual-polarization measurements, which provide information about the snow particle shape and orientation, and multi-frequency measurements, which provide information about size and density. This study combines these techniques with the NASA D3R radar, which provides dual-frequency polarimetric measurements, with data that were observed during the 2018 Winter Olympics.
Fraser King, George Duffy, Lisa Milani, Christopher G. Fletcher, Claire Pettersen, and Kerstin Ebell
Atmos. Meas. Tech., 15, 6035–6050, https://doi.org/10.5194/amt-15-6035-2022, https://doi.org/10.5194/amt-15-6035-2022, 2022
Short summary
Short summary
Under warmer global temperatures, precipitation patterns are expected to shift substantially, with critical impact on the global water-energy budget. In this work, we develop a deep learning model for predicting snow and rain accumulation based on surface radar observations of the lower atmosphere. Our model demonstrates improved skill over traditional methods and provides new insights into the regions of the atmosphere that provide the most significant contributions to high model accuracy.
S. Joseph Munchak, Robert S. Schrom, Charles N. Helms, and Ali Tokay
Atmos. Meas. Tech., 15, 1439–1464, https://doi.org/10.5194/amt-15-1439-2022, https://doi.org/10.5194/amt-15-1439-2022, 2022
Short summary
Short summary
The ability to measure snowfall with weather radar has greatly advanced with the development of techniques that utilize dual-polarization measurements, which provide information about the snow particle shape and orientation, and multi-frequency measurements, which provide information about size and density. This study combines these techniques with the NASA D3R radar, which provides dual-frequency polarimetric measurements, with data that were observed during the 2018 Winter Olympics.
Heather Guy, Ian M. Brooks, Ken S. Carslaw, Benjamin J. Murray, Von P. Walden, Matthew D. Shupe, Claire Pettersen, David D. Turner, Christopher J. Cox, William D. Neff, Ralf Bennartz, and Ryan R. Neely III
Atmos. Chem. Phys., 21, 15351–15374, https://doi.org/10.5194/acp-21-15351-2021, https://doi.org/10.5194/acp-21-15351-2021, 2021
Short summary
Short summary
We present the first full year of surface aerosol number concentration measurements from the central Greenland Ice Sheet. Aerosol concentrations here have a distinct seasonal cycle from those at lower-altitude Arctic sites, which is driven by large-scale atmospheric circulation. Our results can be used to help understand the role aerosols might play in Greenland surface melt through the modification of cloud properties. This is crucial in a rapidly changing region where observations are sparse.
Elin A. McIlhattan, Claire Pettersen, Norman B. Wood, and Tristan S. L'Ecuyer
The Cryosphere, 14, 4379–4404, https://doi.org/10.5194/tc-14-4379-2020, https://doi.org/10.5194/tc-14-4379-2020, 2020
Short summary
Short summary
Snowfall builds the mass of the Greenland Ice Sheet (GrIS) and reduces melt by brightening the surface. We present satellite observations of GrIS snowfall events divided into two regimes: those coincident with ice clouds and those coincident with mixed-phase clouds. Snowfall from ice clouds plays the dominant role in building the GrIS, producing ~ 80 % of total accumulation. The two regimes have similar snowfall frequency in summer, brightening the surface when solar insolation is at its peak.
Jie Gong, Xiping Zeng, Dong L. Wu, S. Joseph Munchak, Xiaowen Li, Stefan Kneifel, Davide Ori, Liang Liao, and Donifan Barahona
Atmos. Chem. Phys., 20, 12633–12653, https://doi.org/10.5194/acp-20-12633-2020, https://doi.org/10.5194/acp-20-12633-2020, 2020
Short summary
Short summary
This work provides a novel way of using polarized passive microwave measurements to study the interlinked cloud–convection–precipitation processes. The magnitude of differences between polarized radiances is found linked to ice microphysics (shape, size, orientation and density), mesoscale dynamic and thermodynamic structures, and surface precipitation. We conclude that passive sensors with multiple polarized channel pairs may serve as cheaper and useful substitutes for spaceborne radar sensors.
Ralf Bennartz, Frank Fell, Claire Pettersen, Matthew D. Shupe, and Dirk Schuettemeyer
Atmos. Chem. Phys., 19, 8101–8121, https://doi.org/10.5194/acp-19-8101-2019, https://doi.org/10.5194/acp-19-8101-2019, 2019
Short summary
Short summary
The Greenland Ice Sheet (GrIS) is rapidly melting. Snowfall is the only source of ice mass over the GrIS. We use satellite observations to assess how much snow on average falls over the GrIS and what the annual cycle and spatial distribution of snowfall is. We find the annual mean snowfall over the GrIS inferred from CloudSat to be 34 ± 7.5 cm yr−1 liquid equivalent.
Claire Pettersen, Ralf Bennartz, Aronne J. Merrelli, Matthew D. Shupe, David D. Turner, and Von P. Walden
Atmos. Chem. Phys., 18, 4715–4735, https://doi.org/10.5194/acp-18-4715-2018, https://doi.org/10.5194/acp-18-4715-2018, 2018
Short summary
Short summary
A novel method for classifying Arctic precipitation using ground based remote sensors is presented. The classification reveals two distinct, primary regimes of precipitation over the central Greenland Ice Sheet: snowfall coupled to deep, fully glaciated ice clouds or to shallow, mixed-phase clouds. The ice clouds are associated with low-pressure storm systems from the southeast, while the mixed-phase clouds slowly propagate from the southwest along a quiescent flow.
Claire Pettersen, Ralf Bennartz, Mark S. Kulie, Aronne J. Merrelli, Matthew D. Shupe, and David D. Turner
Atmos. Chem. Phys., 16, 4743–4756, https://doi.org/10.5194/acp-16-4743-2016, https://doi.org/10.5194/acp-16-4743-2016, 2016
Short summary
Short summary
We examined four summers of data from a ground-based atmospheric science instrument suite at Summit Station, Greenland, to isolate the signature of the ice precipitation. By using a combination of instruments with different specialities, we identified a passive microwave signature of the ice precipitation. This ice signature compares well to models using synthetic data characteristic of the site.
Related subject area
Subject: Others (Wind, Precipitation, Temperature, etc.) | Technique: In Situ Measurement | Topic: Validation and Intercomparisons
Comparison of GRUAN data products for Meisei iMS-100 and Vaisala RS92 radiosondes at Tateno, Japan
Validation of the Aeolus Level-2B wind product over Northern Canada and the Arctic
Boundary-layer height and surface stability at Hyytiälä, Finland, in ERA5 and observations
Characterizing and correcting the warm bias observed in Aircraft Meteorological Data Relay (AMDAR) temperature observations
Something fishy going on? Evaluating the Poisson hypothesis for rainfall estimation using intervalometers: results from an experiment in Tanzania
Suitability of fibre-optic distributed temperature sensing for revealing mixing processes and higher-order moments at the forest–air interface
Validation of Aeolus winds using radiosonde observations and numerical weather prediction model equivalents
Smartphone pressure data: quality control and impact on atmospheric analysis
Automated precipitation monitoring with the Thies disdrometer: biases and ways for improvement
More science with less: evaluation of a 3D-printed weather station
Characteristics and performance of wind profiles as observed by the radar wind profiler network of China
Confronting the boundary layer data gap: evaluating new and existing methodologies of probing the lower atmosphere
On the estimation of vertical air velocity and detection of atmospheric turbulence from the ascent rate of balloon soundings
Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar
Using computational fluid dynamics and field experiments to improve vehicle-based wind measurements for environmental monitoring
Comparison of the GRUAN data products for Meisei RS-11G and Vaisala RS92-SGP radiosondes at Tateno (36.06° N, 140.13° E), Japan
A method to assess the accuracy of sonic anemometer measurements
Using reference radiosondes to characterise NWP model uncertainty for improved satellite calibration and validation
Evaluation of OAFlux datasets based on in situ air–sea flux tower observations over Yongxing Island in 2016
Characteristics of vertical velocities estimated from drop size and fall velocity spectra of a Parsivel disdrometer
Effects of temporal averaging on short-term irradiance variability under mixed sky conditions
Comparison of Lyman-alpha and LI-COR infrared hygrometers for airborne measurement of turbulent fluctuations of water vapour
Hotplate precipitation gauge calibrations and field measurements
Field intercomparison of prevailing sonic anemometers
A new method for estimating UV fluxes at ground level in cloud-free conditions
Precipitable water characteristics during the 2013 Colorado flood using ground-based GPS measurements
Comparison of Vaisala radiosondes RS41 and RS92 launched over the oceans from the Arctic to the tropics
Comparison of hourly surface downwelling solar radiation estimated from MSG–SEVIRI and forecast by the RAMS model with pyranometers over Italy
Quantitative analysis of the radiation error for aerial coiled-fiber-optic distributed temperature sensing deployments using reinforcing fabric as support structure
An automated method for the evaluation of the pointing accuracy of Sun-tracking devices
Assessment of snowfall accumulation underestimation by tipping bucket gauges in the Spanish operational network
Compatibility of different measurement techniques of global solar radiation and application for long-term observations at Izaña Observatory
Uncertainties of ground-based microwave radiometer retrievals in zenith and off-zenith observations under snow conditions
Performance of post-processing algorithms for rainfall intensity using measurements from tipping-bucket rain gauges
Comparison of Vaisala radiosondes RS41 and RS92 at the ARM Southern Great Plains site
HOAPS and ERA-Interim precipitation over the sea: validation against shipboard in situ measurements
Quality assessment of solar UV irradiance measured with array spectroradiometers
Spatial mapping of ground-based observations of total ozone
Performance of WVSS-II hygrometers on the FAAM research aircraft
Solar irradiances measured using SPN1 radiometers: uncertainties and clues for development
Statistical modelling of collocation uncertainty in atmospheric thermodynamic profiles
Estimation of atmospheric mixing layer height from radiosonde data
Assessment of GPS radiosonde descent data
Trajectory matching of ozonesondes and MOZAIC measurements in the UTLS – Part 1: Method description and application at Payerne, Switzerland
A comparison of rainfall measurements from multiple instruments
Eddy-covariance flux measurements with a weight-shift microlight aircraft
Comparisons of temperature, pressure and humidity measurements by balloon-borne radiosondes and frost point hygrometers during MOHAVE-2009
First national intercomparison of solar ultraviolet radiometers in Italy
Shunsuke Hoshino, Takuji Sugidachi, Kensaku Shimizu, Eriko Kobayashi, Masatomo Fujiwara, and Masami Iwabuchi
Atmos. Meas. Tech., 15, 5917–5948, https://doi.org/10.5194/amt-15-5917-2022, https://doi.org/10.5194/amt-15-5917-2022, 2022
Short summary
Short summary
GRUAN data products (GDPs) from Meisei iMS-100 and Vaisala RS92 were compared with 59 dual sounding data. For daytime observations, the iMS-100 temperature is around 0.5 K lower than RS92-GDP in the stratosphere, but for nighttime observations, the difference is around −0.1 K, and data are mostly in agreement. For relative humidity (RH), iMS-100 is around 1–2 % RH higher in the troposphere and 1 % RH smaller in the stratosphere than RS92, but both GDPs are in agreement for most of the profile.
Chih-Chun Chou, Paul J. Kushner, Stéphane Laroche, Zen Mariani, Peter Rodriguez, Stella Melo, and Christopher G. Fletcher
Atmos. Meas. Tech., 15, 4443–4461, https://doi.org/10.5194/amt-15-4443-2022, https://doi.org/10.5194/amt-15-4443-2022, 2022
Short summary
Short summary
Aeolus is the first satellite that provides global wind profile measurements. The mission aims to improve the weather forecasts in the tropics, but also, potentially, in the polar regions. We evaluate the performance of the instrument over the Canadian North and the Arctic by comparing its measured winds in both cloudy and non-cloudy layers to wind data from forecasts, reanalysis, and ground-based instruments. Overall, good agreement was seen, but Aeolus winds have greater dispersion.
Victoria Anne Sinclair, Jenna Ritvanen, Gabin Urbancic, Irina Statnaia, Yurii Batrak, Dmitri Moisseev, and Mona Kurppa
Atmos. Meas. Tech., 15, 3075–3103, https://doi.org/10.5194/amt-15-3075-2022, https://doi.org/10.5194/amt-15-3075-2022, 2022
Short summary
Short summary
We investigate the boundary-layer (BL) height and surface stability in southern Finland using radiosondes, a microwave radiometer and ERA5 reanalysis. Accurately quantifying the BL height is challenging, and the diagnosed BL height can depend strongly on the method used. Microwave radiometers provide reliable estimates of the BL height but only in unstable conditions. ERA5 captures the BL height well except under very stable conditions, which occur most commonly at night during the warm season.
Siebren de Haan, Paul M. A. de Jong, and Jitze van der Meulen
Atmos. Meas. Tech., 15, 811–818, https://doi.org/10.5194/amt-15-811-2022, https://doi.org/10.5194/amt-15-811-2022, 2022
Short summary
Short summary
AMDAR temperatures suffer from a bias, which can be related to a difference in the timing of height and measurement and to internal corrections applied to pressure altitude. Based on NWP model temperature data, combined with Mach number and true airspeed, we could estimate corrections. Comparing corrected temperatures with (independent) radiosonde observations demonstrates a reduction in the bias, from 0.5 K to around zero, and standard deviation, of almost 10 %.
Didier de Villiers, Marc Schleiss, Marie-Claire ten Veldhuis, Rolf Hut, and Nick van de Giesen
Atmos. Meas. Tech., 14, 5607–5623, https://doi.org/10.5194/amt-14-5607-2021, https://doi.org/10.5194/amt-14-5607-2021, 2021
Short summary
Short summary
Ground-based rainfall observations across the African continent are sparse. We present a new and inexpensive rainfall measuring instrument (the intervalometer) and use it to derive reasonably accurate rainfall rates. These are dependent on a fundamental assumption that is widely used in parameterisations of the rain drop size distribution. This assumption is tested and found to not apply for most raindrops but is still useful in deriving rainfall rates. The intervalometer shows good potential.
Olli Peltola, Karl Lapo, Ilkka Martinkauppi, Ewan O'Connor, Christoph K. Thomas, and Timo Vesala
Atmos. Meas. Tech., 14, 2409–2427, https://doi.org/10.5194/amt-14-2409-2021, https://doi.org/10.5194/amt-14-2409-2021, 2021
Short summary
Short summary
We evaluated the suitability of fiber-optic distributed temperature sensing (DTS) for observing spatial (>25 cm) and temporal (>1 s) details of airflow within and above forests. The DTS measurements could discern up to third-order moments of the flow and observe spatial details of coherent flow motions. Similar measurements are not possible with more conventional measurement techniques. Hence, the DTS measurements will provide key insights into flows close to roughness elements, e.g. trees.
Anne Martin, Martin Weissmann, Oliver Reitebuch, Michael Rennie, Alexander Geiß, and Alexander Cress
Atmos. Meas. Tech., 14, 2167–2183, https://doi.org/10.5194/amt-14-2167-2021, https://doi.org/10.5194/amt-14-2167-2021, 2021
Short summary
Short summary
This study provides an overview of validation activities to determine the Aeolus HLOS wind errors and to understand the biases by investigating possible dependencies and testing bias correction approaches. To ensure meaningful validation statistics, collocated radiosondes and two different global NWP models, the ECMWF IFS and the ICON model (DWD), are used as reference data. To achieve an estimate for the Aeolus instrumental error the representativeness errors for the comparisons are evaluated.
Rumeng Li, Qinghong Zhang, Juanzhen Sun, Yun Chen, Lili Ding, and Tian Wang
Atmos. Meas. Tech., 14, 785–801, https://doi.org/10.5194/amt-14-785-2021, https://doi.org/10.5194/amt-14-785-2021, 2021
Short summary
Short summary
In this paper, we describe a bias-correction method based on machine learning without the need to obtain users' personal information and demonstrate that the method can effectively reduce the bias in smartphone pressure observations. The characteristics of this dataset are discussed, and the potential application of the bias-corrected data is illustrated by the fine-scale analysis of a hailstorm that occurred on 10 June 2016 in Beijing, China.
Michael Fehlmann, Mario Rohrer, Annakaisa von Lerber, and Markus Stoffel
Atmos. Meas. Tech., 13, 4683–4698, https://doi.org/10.5194/amt-13-4683-2020, https://doi.org/10.5194/amt-13-4683-2020, 2020
Short summary
Short summary
The Thies disdrometer is used to monitor precipitation intensity and its phase and thus may provide valuable information for the management of meteorological and hydrological risks. In this study, we characterize biases of this instrument using common reference instruments at a pre-alpine study site in Switzerland. We find a systematic underestimation of liquid precipitation amounts and suggest possible reasons for and corrections to this bias and relate these findings to other study sites.
Adam Theisen, Max Ungar, Bryan Sheridan, and Bradley G. Illston
Atmos. Meas. Tech., 13, 4699–4713, https://doi.org/10.5194/amt-13-4699-2020, https://doi.org/10.5194/amt-13-4699-2020, 2020
Short summary
Short summary
A low-cost weather station with 3D-printed components was built, based on the UCAR 3D-PAWS project, and deployed alongside an Oklahoma Mesonet station for an 8-month study to determine the longevity of these sensors and their performance compared with standard commercial sensors. Results show that the low-cost sensors can perform as well as the more expensive commercial ones for short-term deployments with the possibility for long-term deployments with proper maintenance and replacement.
Boming Liu, Jianping Guo, Wei Gong, Lijuan Shi, Yong Zhang, and Yingying Ma
Atmos. Meas. Tech., 13, 4589–4600, https://doi.org/10.5194/amt-13-4589-2020, https://doi.org/10.5194/amt-13-4589-2020, 2020
Short summary
Short summary
Vertical wind profiles are crucial to a wide range of atmospheric disciplines. However, the wind profile across China remains poorly understood. Here we reveal the salient features of winds from the radar wind profile of China, including the main instruments, spatial coverage and sampling frequency. This work is expected to allow the public and scientific community to be more familiar with the nationwide network and encourage the use of these valuable data in future research and applications.
Tyler M. Bell, Brian R. Greene, Petra M. Klein, Matthew Carney, and Phillip B. Chilson
Atmos. Meas. Tech., 13, 3855–3872, https://doi.org/10.5194/amt-13-3855-2020, https://doi.org/10.5194/amt-13-3855-2020, 2020
Short summary
Short summary
It is well known that the atmospheric boundary layer is under-sampled in the vertical dimension. Recently, weather-sensing uncrewed aerial systems (WxUAS) have created new opportunities to sample this region of the atmosphere. This study compares a WxUAS developed at the University of Oklahoma to ground-based remote sensing and radiosondes. We find that overall the systems generally agreed well both thermodynamically and kinematically. However, there is still room to improve each system.
Hubert Luce and Hiroyuki Hashiguchi
Atmos. Meas. Tech., 13, 1989–1999, https://doi.org/10.5194/amt-13-1989-2020, https://doi.org/10.5194/amt-13-1989-2020, 2020
Short summary
Short summary
Vertical ascent rate Vb of meteorological balloons is sometimes used for retrieving vertical air velocity, an important parameter for meteorological applications. Comparisons with concurrent radar and unmanned aerial vehicle (UAV) measurements of atmospheric turbulence showed that Vb can be increased in turbulent layers due to the probable decrease in the drag coefficient of the balloon. We conclude that Vb can also potentially be used for the detection of atmospheric turbulence.
Matthias Mauder, Michael Eggert, Christian Gutsmuths, Stefan Oertel, Paul Wilhelm, Ingo Voelksch, Luise Wanner, Jens Tambke, and Ivan Bogoev
Atmos. Meas. Tech., 13, 969–983, https://doi.org/10.5194/amt-13-969-2020, https://doi.org/10.5194/amt-13-969-2020, 2020
Short summary
Short summary
Sonic anemometers are prone to probe-induced flow distortion effects. Here, we present the results of an intercomparison experiment between a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar, which is inherently free of flow distortion. Our results show an agreement of the mean wind velocity measurements and the standard deviations of the vertical wind speed with comparabilities of 0.082 and 0.020 m s−1, respectively. Friction velocity is underestimated by the CSAT3B by 3 %.
Tara Hanlon and David Risk
Atmos. Meas. Tech., 13, 191–203, https://doi.org/10.5194/amt-13-191-2020, https://doi.org/10.5194/amt-13-191-2020, 2020
Short summary
Short summary
In this study, we aimed to improve accuracy of wind speed and direction measurements from an anemometer mounted atop a research vehicle. Controlled field tests and computer simulations showed that the vehicle shape biases airflow above the vehicle. The results indicate that placing an anemometer at a significant height (> 1 m) above the vehicle, and calibrating anemometer measurements for vehicle shape and wind angle, can be effective in reducing bias in measurements of wind speed and direction.
Eriko Kobayashi, Shunsuke Hoshino, Masami Iwabuchi, Takuji Sugidachi, Kensaku Shimizu, and Masatomo Fujiwara
Atmos. Meas. Tech., 12, 3039–3065, https://doi.org/10.5194/amt-12-3039-2019, https://doi.org/10.5194/amt-12-3039-2019, 2019
Short summary
Short summary
The authors carried out dual flights of RS-11G and RS92-SGP radiosondes and investigated the differences in the performance of the radiosondes to help characterize GRUAN data products. A novel aspect of GRUAN data products is that vertically resolved uncertainty estimates and metadata are provided for each sounding and comparison of GRUAN data products is important in securing the temporal homogeneity of climate data records.
Alfredo Peña, Ebba Dellwik, and Jakob Mann
Atmos. Meas. Tech., 12, 237–252, https://doi.org/10.5194/amt-12-237-2019, https://doi.org/10.5194/amt-12-237-2019, 2019
Short summary
Short summary
We propose a method to assess the accuracy of turbulence measurements by sonic anemometers. The idea is to compute the ratio of the vertical to along-wind velocity spectrum within the inertial subrange. We found that the Metek USA-1 and the Campbell CSAT3 sonic anemometers do not show the expected theoretical ratio. A wind-tunnel-based correction recovers the expected ratio for the USA-1. A correction for the CSAT3 does not, illustrating that this sonic anemometer suffers from flow distortion.
Fabien Carminati, Stefano Migliorini, Bruce Ingleby, William Bell, Heather Lawrence, Stuart Newman, James Hocking, and Andrew Smith
Atmos. Meas. Tech., 12, 83–106, https://doi.org/10.5194/amt-12-83-2019, https://doi.org/10.5194/amt-12-83-2019, 2019
Short summary
Short summary
The GRUAN processor is a software developed to collocate radiosonde profiles and numerical weather prediction model fields, simulate top-of-atmosphere brightness temperature at frequencies used by space-borne instruments, and propagate the radiosonde uncertainties in that simulation. This work responds to an identified lack of metrologically traceable characterisation of uncertainties in model fields that are increasingly used for the validation and calibration of space-borne instruments.
Fenghua Zhou, Rongwang Zhang, Rui Shi, Ju Chen, Yunkai He, Dongxiao Wang, and Qiang Xie
Atmos. Meas. Tech., 11, 6091–6106, https://doi.org/10.5194/amt-11-6091-2018, https://doi.org/10.5194/amt-11-6091-2018, 2018
Short summary
Short summary
In this work, successive air–sea heat flux-related data were acquired over the course of a year (01/02/2016–31/01/2017) at the YXASFT on Yongxing Island. Then, seasonal comparisons were conducted for the daily mean surface bulk variables and heat fluxes between the WHOI OAFlux products and YXASFT observations. The conclusions in this paper will provide useful reference for researchers on how to select the appropriate OAFlux datasets in different seasons over the South China Sea.
Dong-Kyun Kim and Chang-Keun Song
Atmos. Meas. Tech., 11, 3851–3860, https://doi.org/10.5194/amt-11-3851-2018, https://doi.org/10.5194/amt-11-3851-2018, 2018
Short summary
Short summary
A new technique to estimate vertical velocities from Parsivel-measured drop and velocity spectra is developed. The estimated vertical velocities (w) were compared with w components of winds measured from the anemometer at the same site. They showed good agreement with each other, suggesting that this technique is reliable and applicable to rainfall studies. With these w values, rainfall characteristics related to up-/downdraft were investigated on the windward and leeward sides of a mountain.
Gerald M. Lohmann and Adam H. Monahan
Atmos. Meas. Tech., 11, 3131–3144, https://doi.org/10.5194/amt-11-3131-2018, https://doi.org/10.5194/amt-11-3131-2018, 2018
Short summary
Short summary
Using high-resolution surface irradiance data with original temporal resolutions between 0.01 s and 1 s from six different locations in the Northern Hemisphere, we characterize the changes in representation of temporal variability resulting from time averaging. Our results indicate that a temporal averaging time scale of around 1 s marks a transition in representing single-point irradiance variability, such that longer averages result in substantial underestimates of variability.
Astrid Lampert, Jörg Hartmann, Falk Pätzold, Lennart Lobitz, Peter Hecker, Katrin Kohnert, Eric Larmanou, Andrei Serafimovich, and Torsten Sachs
Atmos. Meas. Tech., 11, 2523–2536, https://doi.org/10.5194/amt-11-2523-2018, https://doi.org/10.5194/amt-11-2523-2018, 2018
Short summary
Short summary
We compared two different fast-response humidity sensors simultaneously on different airborne platforms. One is a particular, well-establed Lyman-alpha hygrometer that has been used for decades as the standard for fast airborne humidity measurements. However, it is not available any more. The other one is a hygrometer based on the absorption of infrared radiation, from LI-COR. For an environment of low vibrations, the LI-COR sensor is suitable for fast airborne water vapour measurements.
Nicholas Zelasko, Adam Wettlaufer, Bujidmaa Borkhuu, Matthew Burkhart, Leah S. Campbell, W. James Steenburgh, and Jefferson R. Snider
Atmos. Meas. Tech., 11, 441–458, https://doi.org/10.5194/amt-11-441-2018, https://doi.org/10.5194/amt-11-441-2018, 2018
Short summary
Short summary
The hotplate precipitation gauge has the potential to solve some problems with conventional precipitation gauge measurements, especially for snowfall. This paper extends the seminal published work, Rasmussen et al. (2011). We assert that the precipitation rate algorithm we have developed for the hotplate is an improvement on that which was previously published.
Matthias Mauder and Matthias J. Zeeman
Atmos. Meas. Tech., 11, 249–263, https://doi.org/10.5194/amt-11-249-2018, https://doi.org/10.5194/amt-11-249-2018, 2018
William Wandji Nyamsi, Mikko R. A. Pitkänen, Youva Aoun, Philippe Blanc, Anu Heikkilä, Kaisa Lakkala, Germar Bernhard, Tapani Koskela, Anders V. Lindfors, Antti Arola, and Lucien Wald
Atmos. Meas. Tech., 10, 4965–4978, https://doi.org/10.5194/amt-10-4965-2017, https://doi.org/10.5194/amt-10-4965-2017, 2017
Short summary
Short summary
This paper proposes a new, fast and accurate method for estimating UV fluxes at ground level in cloud-free conditions at any place and time. The method performs very well with the Copernicus Atmosphere Monitoring Service products as inputs describing the state of the atmosphere. An accuracy that is close to the uncertainty of the measurements themselves is reached. We believe that our research will be widely used in the near future.
Hannah K. Huelsing, Junhong Wang, Carl Mears, and John J. Braun
Atmos. Meas. Tech., 10, 4055–4066, https://doi.org/10.5194/amt-10-4055-2017, https://doi.org/10.5194/amt-10-4055-2017, 2017
Short summary
Short summary
The precipitable water (PW) was examined for the 2013 Colorado flood to determine how climatologically abnormal this event was. The seasonal PW maximum extended into early September and the September monthly mean PW exceeded the 99th percentile of climatology with a value 25% higher than the 40-year climatology. The above-normal, near-saturation PW values during the flood were the result of large-scale moisture transport into Colorado from the eastern tropical Pacific and the Gulf of Mexico.
Yoshimi Kawai, Masaki Katsumata, Kazuhiro Oshima, Masatake E. Hori, and Jun Inoue
Atmos. Meas. Tech., 10, 2485–2498, https://doi.org/10.5194/amt-10-2485-2017, https://doi.org/10.5194/amt-10-2485-2017, 2017
Short summary
Short summary
The model RS92 radiosonde manufactured by Vaisala Ltd. is now being replaced with a successor model, the RS41, and we need to clarify accuracy differences between them for a variety of research. For this purpose, 36 twin-radiosonde flights were performed over the oceans from the Arctic to the tropics. Basically the differences between the RS41 and RS92 were smaller than the nominal combined uncertainties of the RS41; however, we found non-negligible biases in relative humidity and pressure.
Stefano Federico, Rosa Claudia Torcasio, Paolo Sanò, Daniele Casella, Monica Campanelli, Jan Fokke Meirink, Ping Wang, Stefania Vergari, Henri Diémoz, and Stefano Dietrich
Atmos. Meas. Tech., 10, 2337–2352, https://doi.org/10.5194/amt-10-2337-2017, https://doi.org/10.5194/amt-10-2337-2017, 2017
Short summary
Short summary
In this paper we evaluate the performance of two estimates of the global horizontal irradiance (GHI), one derived from the Meteosat Second Generation and one from a meteorological model (Regional Atmospheric Modeling System) forecast. The focus area is Italy, and the performance is evaluated for 12 pyranometers spanning a range of climate conditions, from Mediterranean maritime to Alpine.
Armin Sigmund, Lena Pfister, Chadi Sayde, and Christoph K. Thomas
Atmos. Meas. Tech., 10, 2149–2162, https://doi.org/10.5194/amt-10-2149-2017, https://doi.org/10.5194/amt-10-2149-2017, 2017
Dietmar J. Baumgartner, Werner Pötzi, Heinrich Freislich, Heinz Strutzmann, Astrid M. Veronig, and Harald E. Rieder
Atmos. Meas. Tech., 10, 1181–1190, https://doi.org/10.5194/amt-10-1181-2017, https://doi.org/10.5194/amt-10-1181-2017, 2017
Short summary
Short summary
In this work we present KSO-STREAMS (KSO-SunTRackEr Accuracy Monitoring System), a platform-independent, fully automated, and cost-effective system to evaluate the pointing accuracy of Sun-tracking devices as well as its application at the Kanzelhöhe Observatory (KSO) Austrian radiation monitoring network (ARAD) site and to the results from a 15-week evaluating period.
Samuel T. Buisán, Michael E. Earle, José Luís Collado, John Kochendorfer, Javier Alastrué, Mareile Wolff, Craig D. Smith, and Juan I. López-Moreno
Atmos. Meas. Tech., 10, 1079–1091, https://doi.org/10.5194/amt-10-1079-2017, https://doi.org/10.5194/amt-10-1079-2017, 2017
Short summary
Short summary
Within the framework of the WMO-SPICE (Solid Precipitation Intercomparison Experiment) the Thies tipping bucket precipitation gauge, widely used at AEMET, was assessed against the SPICE reference.
Most countries use tipping buckets and for this reason the underestimation of snowfall precipitation is a large-scale problem.
The methodology presented here can be used by other national weather services to test precipitation bias corrections and to identify regions where errors are higher.
Rosa Delia García, Emilio Cuevas, Omaira Elena García, Ramón Ramos, Pedro Miguel Romero-Campos, Fernado de Ory, Victoria Eugenia Cachorro, and Angel de Frutos
Atmos. Meas. Tech., 10, 731–743, https://doi.org/10.5194/amt-10-731-2017, https://doi.org/10.5194/amt-10-731-2017, 2017
Short summary
Short summary
A 1-year intercomparison of classical and modern radiation and sunshine duration instruments has been performed at Izaña Atmospheric Observatory. We compare global solar radiation (GSR) records measured with a Kipp & Zonen CM-21 pyranometer, taken in the framework of the Baseline Surface Radiation Network, with those measured with a multifilter rotating shadowband radiometer and a bimetallic pyranometer, and with GSR estimated from sunshine duration performed with a CS sunshine recorder.
Wengang Zhang, Guirong Xu, Yuanyuan Liu, Guopao Yan, Dejun Li, and Shengbo Wang
Atmos. Meas. Tech., 10, 155–165, https://doi.org/10.5194/amt-10-155-2017, https://doi.org/10.5194/amt-10-155-2017, 2017
Short summary
Short summary
A comparison between a microwave radiometer and radiosonde is carried out, and performances of zenith and off-zenith observations during snowfall are shown. In off-zenith observations, the effect of snow is obviously mitigated, and the deviation between microwave radiometer and radiosonde is small. With the aid of off-zenith observation, reliable thermodynamic atmospheric profiles can be collected, and those will be useful for the analysis and forecasting of severe convective weather.
Mattia Stagnaro, Matteo Colli, Luca Giovanni Lanza, and Pak Wai Chan
Atmos. Meas. Tech., 9, 5699–5706, https://doi.org/10.5194/amt-9-5699-2016, https://doi.org/10.5194/amt-9-5699-2016, 2016
Short summary
Short summary
The research presented in this work involves field data analysis, numerical modelling techniques and approaches to a long-standing problem of liquid precipitation measurements: the sampling and the interpretation of the tipping-bucket sensor signal. The present study shows relevant implications of the adopted data processing methods for the accuracy of the rainfall intensity measurements provided by traditional tipping-bucket gauges.
Michael P. Jensen, Donna J. Holdridge, Petteri Survo, Raisa Lehtinen, Shannon Baxter, Tami Toto, and Karen L. Johnson
Atmos. Meas. Tech., 9, 3115–3129, https://doi.org/10.5194/amt-9-3115-2016, https://doi.org/10.5194/amt-9-3115-2016, 2016
Short summary
Short summary
An intercomparison of Vaisala's latest-generation radiosonde RS41 and the widely used RS92 was performed in north-central Oklahoma, USA, during June 2014. The results indicate that for the conditions observed during the intercomparison the measurements of pressure, temperature, humidity, and winds agree to within the manufacturer-specified combined uncertainties. Some important exceptions were noted when exiting liquid cloud layers where evaporative cooling has less impact for RS41 measurements.
Karl Bumke, Gert König-Langlo, Julian Kinzel, and Marc Schröder
Atmos. Meas. Tech., 9, 2409–2423, https://doi.org/10.5194/amt-9-2409-2016, https://doi.org/10.5194/amt-9-2409-2016, 2016
Short summary
Short summary
Satellite-derived HOAPS and ERA-Interim reanalysis data were validated against shipboard precipitation measurements. Results show that HOAPS detects the frequency of precipitation well, while ERA-Interim strongly overestimates it, especially at low latitudes. However, HOAPS underestimates precipitation rates, while ERA-Interim's Atlantic-wide precipitation rate is close to measurements. ERA-Interim strongly overestimates it in the intertropical convergence zone and southern subtropics.
Luca Egli, Julian Gröbner, Gregor Hülsen, Luciano Bachmann, Mario Blumthaler, Jimmy Dubard, Marina Khazova, Richard Kift, Kees Hoogendijk, Antonio Serrano, Andrew Smedley, and José-Manuel Vilaplana
Atmos. Meas. Tech., 9, 1553–1567, https://doi.org/10.5194/amt-9-1553-2016, https://doi.org/10.5194/amt-9-1553-2016, 2016
Short summary
Short summary
Array spectroradiometers are small, light, robust and cost-effective instruments, and are increasingly used for atmospheric measurements. The quality of array spectroradiometers is assessed for the reliable quantification of ultraviolet radiation (UV) in order to monitor the exposure of UV radiation to human health. The study shows that reliable UV measurements with these instruments are limited for observations around noon and show large biases in the morning and evening.
K.-L. Chang, S. Guillas, and V. E. Fioletov
Atmos. Meas. Tech., 8, 4487–4505, https://doi.org/10.5194/amt-8-4487-2015, https://doi.org/10.5194/amt-8-4487-2015, 2015
Short summary
Short summary
The aim of this article is to analyze the total column ozone data from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) that consists of around 150 stations irregularly spaced over the globe. Our use of a new statistical spatial technique over the globe can greatly outperform the currently used spatial approximation of the total column ozone in terms of approximation. We feel that this technique could benefit the ozone science community.
A. K. Vance, S. J. Abel, R. J. Cotton, and A. M. Woolley
Atmos. Meas. Tech., 8, 1617–1625, https://doi.org/10.5194/amt-8-1617-2015, https://doi.org/10.5194/amt-8-1617-2015, 2015
Short summary
Short summary
Comparisons on the FAAM BAe 146-301 aircraft show good agreement between chilled mirror hygrometers and a WVSS-II fed from a modified Rosemount inlet (wvssR) in coud-free conditions, but a WVSS-II fed from the standard flush inlet (wvssF) over-reads, except at higher humidities. Case studies in cloudy conditions show that wvssF is immune to liquid water and ice, whilst wvssR is susceptible to both. Both WVSS-II inlets respond much more rapidly than the chilled mirror devices, especially wvssF.
J. Badosa, J. Wood, P. Blanc, C. N. Long, L. Vuilleumier, D. Demengel, and M. Haeffelin
Atmos. Meas. Tech., 7, 4267–4283, https://doi.org/10.5194/amt-7-4267-2014, https://doi.org/10.5194/amt-7-4267-2014, 2014
A. Fassò, R. Ignaccolo, F. Madonna, B. B. Demoz, and M. Franco-Villoria
Atmos. Meas. Tech., 7, 1803–1816, https://doi.org/10.5194/amt-7-1803-2014, https://doi.org/10.5194/amt-7-1803-2014, 2014
X. Y. Wang and K. C. Wang
Atmos. Meas. Tech., 7, 1701–1709, https://doi.org/10.5194/amt-7-1701-2014, https://doi.org/10.5194/amt-7-1701-2014, 2014
M. Venkat Ratnam, N. Pravallika, S. Ravindra Babu, G. Basha, M. Pramitha, and B. V. Krishna Murthy
Atmos. Meas. Tech., 7, 1011–1025, https://doi.org/10.5194/amt-7-1011-2014, https://doi.org/10.5194/amt-7-1011-2014, 2014
J. Staufer, J. Staehelin, R. Stübi, T. Peter, F. Tummon, and V. Thouret
Atmos. Meas. Tech., 6, 3393–3406, https://doi.org/10.5194/amt-6-3393-2013, https://doi.org/10.5194/amt-6-3393-2013, 2013
X. C. Liu, T. C. Gao, and L. Liu
Atmos. Meas. Tech., 6, 1585–1595, https://doi.org/10.5194/amt-6-1585-2013, https://doi.org/10.5194/amt-6-1585-2013, 2013
S. Metzger, W. Junkermann, M. Mauder, F. Beyrich, K. Butterbach-Bahl, H. P. Schmid, and T. Foken
Atmos. Meas. Tech., 5, 1699–1717, https://doi.org/10.5194/amt-5-1699-2012, https://doi.org/10.5194/amt-5-1699-2012, 2012
D. F. Hurst, E. G. Hall, A. F. Jordan, L. M. Miloshevich, D. N. Whiteman, T. Leblanc, D. Walsh, H. Vömel, and S. J. Oltmans
Atmos. Meas. Tech., 4, 2777–2793, https://doi.org/10.5194/amt-4-2777-2011, https://doi.org/10.5194/amt-4-2777-2011, 2011
H. Diémoz, A. M. Siani, G. R. Casale, A. di Sarra, B. Serpillo, B. Petkov, S. Scaglione, A. Bonino, S. Facta, F. Fedele, D. Grifoni, L. Verdi, and G. Zipoli
Atmos. Meas. Tech., 4, 1689–1703, https://doi.org/10.5194/amt-4-1689-2011, https://doi.org/10.5194/amt-4-1689-2011, 2011
Cited articles
Bliven, L.: GPM Ground Validation Precipitation Imaging Package (PIP) ICE POP V1, NASA Global Hydrology Resource Center DAAC [data set], Huntsville, Alabama, USA, https://doi.org/10.5067/GPMGV/ICEPOP/PIP/DATA101, 2020. a
Fitzgibbon, A. W. and Fisher, R. B.: A Buyer's Guide to Conic Fitting, in:
Proceedings of the British Machine Vision Conference, University of Birmingham, Birmingham, UK, 11–14 September 1995, BMVA
Press, pp. 513–522, https://doi.org/10.5244/C.9.51, 1995. a
Garrett, T. J., Fallgatter, C., Shkurko, K., and Howlett, D.: Fall speed measurement and high-resolution multi-angle photography of hydrometeors in free fall, Atmos. Meas. Tech., 5, 2625–2633, https://doi.org/10.5194/amt-5-2625-2012, 2012. a, b, c
Heymsfield, A. J. and Westbrook, C. D.: Advances in the estimation of ice
particle fall speeds using laboratory and field measurements, J. Atmos.
Sci., 67, 2469–2482, https://doi.org/10.1175/2010JAS3379.1, 2010. a
Huang, G.-J., Bringi, V. N., Cifelli, R., Hudak, D., and Petersen, W. A.: A
methodology to derive radar reflectivity-liquid equivalent snow rate
relations using C-band radar and a 2D video disdrometer, J. Atmos.
Oceanic Technol., 27, 637–651, https://doi.org/10.1175/2009JTECHA1284.1, 2010. a
Jameson, G.: Inequalities for the perimeter of an ellipse, Math. Gaz., 98, 227–234, https://doi.org/10.1017/S002555720000125X, 2014. a
Jiang, Z., Oue, M., Verlinde, J., Clothiaux, E. E., Aydin, K., Botta, G., and
Lu, Y.: What can we conclude about the real aspect ratios of ice particle
aggregates from two-dimensional images?, J. Appl. Meteor. Climatol., 56,
725–734, https://doi.org/10.1175/JAMC-D-16-0248.1, 2017. a
Korolev, A. and Isaac, G.: Roundness and Aspect Ratio of Particles in Ice
Clouds, J. Atmos. Sci., 60, 1795–1808,
https://doi.org/10.1175/1520-0469(2003)060<1795:RAAROP>2.0.CO;2, 2003. a
Lee, G. and Kim, K.: International Collaborative Experiments for
PyeongChang 2018 Olympic and Paralympic winter games (ICE-POP 2018),
in: AGU Fall Meeting, San Francisco, CA, 9–13 December 2019, https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/579526 (last access: 14 November 2022), 2019. a
Leinonen, J., Grazioli, J., and Berne, A.: Reconstruction of the mass and geometry of snowfall particles from multi-angle snowflake camera (MASC) images, Atmos. Meas. Tech., 14, 6851–6866, https://doi.org/10.5194/amt-14-6851-2021, 2021. a, b, c
Lim, K.-S. S., Chang, E.-C., Sun, R., Kim, K., Tapiador, F. J., and Lee, G.:
Evaluation of simulated winter precipitation using WRF-ARW during the ICE-POP
2018 field campaign, Weather Forecast., 35, 2199–2213,
https://doi.org/10.1175/WAF-D-19-0236.1, 2020. a
Locatelli, J. D. and Hobbs, P. V.: Fall speeds and masses of solid
precipitation particles, J. Geophys. Res., 79, 2185–2197,
https://doi.org/10.1029/JC079i015p02185, 1974. a
Matrosov, S. Y., Heymsfield, A. J., and Wang, Z.: Dual-frequency radar ratio of
nonspherical atmopsheric hydrometeors, Geophys. Res. Lett., 32, L13816,
https://doi.org/10.1029/2005GL023210, 2005. a
Munchak, S. J., Schrom, R. S., Helms, C. N., and Tokay, A.: Snow microphysical retrieval from the NASA D3R radar during ICE-POP 2018, Atmos. Meas. Tech., 15, 1439–1464, https://doi.org/10.5194/amt-15-1439-2022, 2022. a
Newman, A. J., Kucera, P. A., and Bliven, L. F.: Presenting the snowflake video
imager (SVI), J. Atmos. Oceanic Technol., 26, 167–179,
https://doi.org/10.1175/2008JTECHA1148.1, 2009. a, b
Pettersen, C., Bliven, L. F., von Lerber, A., Wood, N. B., Kulie, M. S.,
Mateling, M. E., Moisseev, D. N., Munchak, S. J., Petersen, W. A., and Wolff,
D. B.: The Precipitation Imaging Package: Assessment of microphysical
and bulk characteristics of snow, Atmosphere, 11, 785,
https://doi.org/10.3390/atmos11080785, 2020. a, b, c
Pettersen, C., Bliven, L. F., Kulie, M. S., Wood, N. B., Shates, J. A.,
Anderson, J., Mateling, M. E., Petersen, W. A., von Lerber, A., and Wolff,
D. B.: The precipitation imaging package: Phase partitioning capabilities,
Remote Sens., 13, 2183, https://doi.org/10.3390/rs13112183, 2021. a, b
Schönhuber, M., Lammer, G., and Randeu, W. L.: The 2D-video-distrometer,
in: Precipitation: Advances in measurement, estimation and prediction,
edited by: Michaelides, S., Springer, 1st edn., pp. 3–31, https://doi.org/10.1007/978-3-540-77655-0, 2008. a
Shkurko, K., Garrett, T., and Gaustad, K.: Multi-Angle Snowflake Camera
Value-Added Product, DOE Office of
Science Atmospheric Radiation Measurement (ARM) Program, DOE/ARM Tech. Rep. DOE/SC-ARM-TR-187,
https://doi.org/10.2172/1342901, 2016. a, b
Stuefer, M. and Bailey, J.: Multi-Angle Snowflake Camera Instrument
Handbook, DOE Office of Science
Atmospheric Radiation Measurement (ARM) Program, DOE/ARM Tech. Rep. DOE/SC-ARM-TR-158, https://doi.org/10.2172/1261185, 2016. a
Tapiador, F. J., Villalba-Pradas, A., Navarro, A., García-Ortega, E., Lim,
K.-S. S., Ahn, K. D., and Lee, G.: Future directions in precipitation
science, Remote Sens., 13, 1074, https://doi.org/10.3390/rs13061074, 2021. a
Tyynelä, J., Leinonen, J., Moisseev, D., and Nousiainen, T.: Radar
Backscattering from Snowflakes: Comparison of Fractal, Aggregate, and Soft
Spheroid Models, J. Atmos. Oceanic Technol., 28, 1365–1372,
https://doi.org/10.1175/JTECH-D-11-00004.1, 2011. a
von Lerber, A., Moisseev, D., Bliven, L. F., Petersen, W., Harri, A.-M., and
Chandrasekar, V.: Microphysical properties of snow and their link to Ze-S
relations during BAECC 2014, J. Appl. Meteor. Climatol., 56, 1561–1582,
https://doi.org/10.1175/JAMC-D-16-0379.1, 2017.
a
Westbrook, C. D.: Rayleigh scattering by hexagonal ice crystals and the
interpretation of dual-polarization radar measurements, Q. J. Roy.
Meteor. Soc., 140, 2090–2096, https://doi.org/10.1002/qj.2262, 2014. a
Wood, N. B., L'Ecuyer, T. S., Bliven, F. L., and Stephens, G. L.: Characterization of video disdrometer uncertainties and impacts on estimates of snowfall rate and radar reflectivity, Atmos. Meas. Tech., 6, 3635–3648, https://doi.org/10.5194/amt-6-3635-2013, 2013. a
Short summary
This study compares the techniques used to measure snowflake shape by three instruments: PIP, MASC, and 2DVD. Our findings indicate that the MASC technique produces reliable shape measurements; the 2DVD technique performs better than expected considering the instrument was designed to measure raindrops; and the PIP technique does not produce reliable snowflake shape measurements. We also demonstrate that the PIP images can be reprocessed to correct the shape measurement issues.
This study compares the techniques used to measure snowflake shape by three instruments: PIP,...
