Atmospheric electric field in the Atlantic marine boundary layer: first results from the SAIL project

The study of the electrical properties of the atmospheric marine boundary layer is important as the effect of natural radioactivity in driving near surface ionisation is significantly reduced over the ocean, and the concentration of aerosols is also typically lower than over continental areas, allowing a clearer examination of space-atmosphere interactions. Furthermore, cloud cover over the ocean is dominated by low-level clouds and most of the atmospheric charge lies near the earth surface, at low altitude cloud tops. The relevance of electric field observations in the marine boundary layer is enhanced by the the fact that the electrical conductivity of the ocean air is clearly linked to global atmospheric pollution and aerosol content. The increase in aerosol pollution since the original observations made in the early 20th century by the survey ship Carnegie is a pressing and timely motivation for modern measurements of the atmospheric electric field in the marine boundary layer. Project SAIL (Space-Atmosphere-Ocean Interactions in the marine boundary Layer) addresses this challenge by means of an unique monitoring campaign on board the ship-rigged sailing ship NRP Sagres during its 2020 circumnavigation expedition. The Portuguese Navy ship NRP Sagres departed from Lisbon on January 5th in a journey around the globe that will take 371 days. Two identical field mill sensors (CS110, Campbell Scientific) are installed on the mizzen mast, one at a height of 22 m, and the other at a height of 5 meters. A visibility sensor (SWS050, Biral) was also set-up on the same mast in order to have measurements of the extinction coefficient of the atmosphere and assess fair-weather conditions. Further observations include gamma radiation measured with a NaI(Tl) scintillator from 475 keV to 3 MeV, cosmic radiation up to 17 MeV, and atmospheric ionisation from a cluster ion counter (Airel). The 1 Hz measurements of the atmospheric electric field and from all the other sensors are linked to the same rigorous temporal reference frame and precise positioning through kinematic GNSS observations. Here the first results of the SAIL project will be presented, focusing on fair-weather electric field over the Atlantic. The observations obtained in the first three sections of the circumnavigation journey, including Lisbon (Portugal) - Tenerife (Spain), from 5 to 10 January, Tenerife - Praia (Cape Verde) from 13 to 19 January, and across the Atlantic from Cape Verde to Rio de Janeiro (Brasil), from January 22nd to February 14th, will be presented and discussed.

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Variability of the atmospheric electric field in the South Atlantic marine boundary layer from the SAIL campaign

10.5194/egusphere-egu21-1243 ◽

2021 ◽

Author(s):

Susana Barbosa ◽

Mauricio Camilo ◽

Carlos Almeida ◽

Guilherme Amaral ◽

Nuno Dias ◽

...

Keyword(s):

Boundary Layer ◽

Electric Field ◽

Buenos Aires ◽

Marine Boundary Layer ◽

South Atlantic ◽

Atmospheric Electric Field ◽

Surface Ionization ◽

Diurnal Pattern ◽

The South ◽

Near Surface

The marine boundary layer offers a unique opportunity to investigate the electrical properties of the atmosphere, as the effect of natural radioactivity in driving near surface ionization is significantly reduced over the ocean, and the concentration of aerosols is also typically lower than over land. This work addresses the temporal variability of the atmospheric electric field in the South Atlantic marine boundary layer based on measurements from the SAIL (Space-Atmosphere-Ocean Interactions in the marine boundary Layer) project. The SAIL monitoring campaign took place on board the Portuguese navy tall ship NRP Sagres during its circumnavigation expedition in 2020.&#160; Two identical field mills (CS110, Campbell Scientific) were installed on the same mast but at different heights (about 5 and 22 meters), recording the atmospheric electric field every 1-second. Hourly averages of the atmospheric electric field are analyzed for the ship&#8217;s leg from 3rd to 25th March, between Buenos Aires (South America) and Cape Town (South Africa). The median daily curve of the electric field has a shape compatible with the Carnegie curve, but significant variability is found in the daily pattern of individual days, with only about 30% of the days exhibiting a diurnal pattern consistent with the Carnegie curve.

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Periodic variations of atmospheric electric field on fair weather conditions at YBJ, Tibet

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2013.02.013 ◽

2013 ◽

Vol 97 ◽

pp. 85-90 ◽

Cited By ~ 11

Author(s):

Bin Xu ◽

Dan Zou ◽

Ben Yuan Chen ◽

Jin Ye Zhang ◽

Guo Wang Xu

Keyword(s):

Electric Field ◽

Weather Conditions ◽

Atmospheric Electric Field ◽

Fair Weather

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Seasonal and annual variations in the strength of the atmospheric electric field in the 24th cycle of solar activity measured in Yakutsk

E3S Web of Conferences ◽

10.1051/e3sconf/202019601009 ◽

2020 ◽

Vol 196 ◽

pp. 01009

Author(s):

Anatoliy Toropov ◽

Vladimir Kozlov ◽

Rustam Karimov

Keyword(s):

Solar Activity ◽

Field Strength ◽

Electric Field ◽

Data Acquisition ◽

Weather Conditions ◽

Data Acquisition System ◽

Atmospheric Electric Field ◽

Fair Weather ◽

Annual Variations ◽

24Th Cycle

The paper presents the results of measuring the strength of the atmospheric electric field in fair weather conditions in the 24th cycle of solar activity from 2009 to 2019 according to observations in Yakutsk (North-east of Siberia). Intensity of the atmospheric electric field measurements by an electric field-mill sensor, mounted on the roof of the main building of the SchICRA SB RAS (N 62 ° 1 ‘, E129 ° 43’) in Yakutsk. The field-mill sensor has a measurement range of the atmospheric electric field strength +/- 50 kV/m with an accuracy of +/- 1 V/m. The data acquisition system based on a personal computer and an analog-to-digital converter (ADC) E 14-440 L-Card. Data is written to the hard disc drive of the data acquisition system with a one second resolution data. Based on the analysis of data on the atmospheric electric field from 2009 to 2019 it was found that the seasonal variation of the monthly mean values of the field strength has maxima in the spring and autumn months and minima in the summer and winter months. Annual variations of the field strength in fair weather conditions over the observation period have a general trend towards a decrease in the field strength.

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Joint Anomalies of High-Frequency Geoacoustic Emission and Atmospheric Electric Field by the Ground–Atmosphere Boundary in a Seismically Active Region (Kamchatka)

Atmosphere ◽

10.3390/atmos10050267 ◽

2019 ◽

Vol 10 (5) ◽

pp. 267 ◽

Cited By ~ 1

Author(s):

Yury Marapulets ◽

Oleg Rulenko

Keyword(s):

Electric Field ◽

High Frequency ◽

Weather Conditions ◽

Atmospheric Electric Field ◽

Near Surface ◽

Geoacoustic Emission ◽

Sign Change ◽

The Common ◽

Calm Weather ◽

Short Time

The authors generalize and analyze the investigation results of joint anomalies of high-frequency geoacoustic emission and atmospheric electric field by the ground–atmosphere boundary which were detected by them in Kamchatka. These anomalies are observed as geoacoustic emission increases in kilohertz frequency range and bay-like decreases of atmospheric electric field with the sign change which occur close in time during calm weather conditions. It is the authors’ opinion that the common nature of these anomalies is short-time stretching of the near-surface sedimentary rocks at an observation site during unstable tectono-seismic process. A scheme of the detected anomalies formation has been suggested.

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A Study of the Effects of Rain, Snow and Hail on the Atmospheric Electric Field near Ground

Atmosphere ◽

10.3390/atmos12080996 ◽

2021 ◽

Vol 12 (8) ◽

pp. 996

Author(s):

Athanasios Karagioras ◽

Konstantinos Kourtidis

Keyword(s):

Frequency Distribution ◽

Complex Structure ◽

Potential Gradient ◽

Weather Conditions ◽

The Other ◽

Fair Weather ◽

Northern Greece ◽

Rain Events ◽

The Impact ◽

Bounce Back

The purpose of the present study is to investigate the impact of rain, snow and hail on potential gradient (PG), as observed in a period of ten years in Xanthi, northern Greece. An anticorrelation between PG and rainfall was observed for rain events that lasted several hours. When the precipitation rate was up to 2 mm/h, the decrease in PG was between 200 and 1300 V/m, in most cases being around 500 V/m. An event with rainfall rates up to 11 mm/h produced the largest drop in PG, of 2 kV/m. Shortly after rain, PG appeared to bounce back to somewhat higher values than the ones of fair-weather conditions. A decrease in mean hourly PG was observed, which was around 2–4 kV/m during the hail events which occurred concurrently with rain and from 0 to 3.5 kV/m for hail events with no rain. In the case of no drop, no concurrent drop in temperature was observed, while, for the other cases, it appeared that, for each degree drop in temperature, the drop in hourly mean PG was 1000 V/m; hence, we assume that the intensity of the hail event regulates the drop in PG. The frequency distribution of 1-minute PG exhibits a complex structure during hail events and extend from −18 to 11 kV/m, with most of the values in the negative range. During snow events, 1-minute PG exhibited rapid fluctuations between high positive and high negative values, its frequency distribution extending from −10 to 18 kV/m, with peaks at −10 and 3 kV/m.

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Atmospheric electric field variations during fair weather and thunderstorms at different altitudes

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2020.105452 ◽

2020 ◽

Vol 211 ◽

pp. 105452

Author(s):

Hripsime Mkrtchyan ◽

Gayane Karapetyan ◽

Davit Aslanyan

Keyword(s):

Electric Field ◽

Atmospheric Electric Field ◽

Fair Weather ◽

Different Altitudes

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Effects of Large Eddies on the Structure of the Marine Boundary Layer under Strong Wind Conditions

Journal of the Atmospheric Sciences ◽

10.1175/jas-3342.1 ◽

2004 ◽

Vol 61 (24) ◽

pp. 3049-3064 ◽

Cited By ~ 28

Author(s):

Isaac Ginis ◽

Alexander P. Khain ◽

Elena Morozovsky

Keyword(s):

Boundary Layer ◽

Wind Speed ◽

Marine Boundary Layer ◽

Sea Surface ◽

Cloud Formation ◽

Strong Wind ◽

Latent Heat Release ◽

Air Humidity ◽

Near Surface ◽

Large Eddies

Abstract A model of the atmospheric boundary layer (BL) is presented that explicitly calculates a two-way interaction of the background flow and convective motions. The model is utilized for investigation of the formation of large eddies (roll vortices) and their effects on the structure of the marine boundary layer under conditions resembling those of tropical cyclones. It is shown that two main factors controlling the formation of large eddies are the magnitude of the background wind speed and air humidity, determining the cloud formation and latent heat release. When the wind speed is high enough, a strong vertical wind shear develops in the lower part of the BL, which triggers turbulent mixing and the formation of a mixed layer. As a result, the vertical profiles of velocity, potential temperature, and mixing ratio in the background flow are modified to allow for the development of large eddies via dynamic instability. Latent heat release in clouds was found to be the major energy source of large eddies. The cloud formation depends on the magnitude of air humidity. The most important manifestation of the effects of large eddies is a significant increase of the near-surface wind speed and evaporation from the sea surface. For strong wind conditions, the increase of the near-surface speed can exceed 10 m s−1 and evaporation from the sea surface can double. These results demonstrate an important role large eddies play in the formation of BL structure in high wind speeds. Inclusion of these effects in the BL parameterizations of tropical cyclone models may potentially lead to substantial improvements in the prediction of storm intensity.

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Atmospheric electric field measurements in the central United Arab Emirates

10.5194/egusphere-egu2020-5707 ◽

2020 ◽

Author(s):

Keri Nicoll ◽

R. Giles Harrison ◽

Graeme Marlton ◽

Martin Airey

Keyword(s):

Electric Field ◽

United Arab Emirates ◽

Daily Variation ◽

Sea Breeze ◽

Abu Dhabi ◽

Atmospheric Electric Field ◽

Fair Weather ◽

Al Ain ◽

Dust Charging ◽

Convection Dominated

Measurements of the atmospheric electric field (or Potential Gradient, PG) in arid, desert regions are few in comparison to those in more wet/mid latitude regions, despite the fact that such measurements can provide important insights into dust charging processes. Dust charging is emerging as potentially important in sustaining the long range transport of particles, for which new charge and field data are essential. Here we present new PG data from an electric field mill at Al Ain international airport in the eastern part of the Abu Dhabi Emirate in the United Arab Emirates (UAE).&#160; Measurements were made alongside a visibility sensor and ceilometer to provide information on the background meteorological conditions.&#160; At Al Ain, the conditions are generally fair weather in mid-latitude terms (predominantly no clouds or precipitation), with very occasional fog or thunderstorms, but the PG still demonstrates considerable variability associated with local factors such as dust and aerosol content.&#160; Throughout the data series, the PG is almost entirely positive, with the only negative values occurring during thunderstorms and violent dust storms.&#160; The desert climate of the UAE lead to widespread uplift of dust on a regular basis, as evidenced by the generally low visibility measured at the airport (mean visibility = 9km).&#160; The PG at Al Ain was found to be generally much larger than typical fair weather values at other sites, with a mean of 116 V/m, with 2 kV/m exceeded regularly.&#160; The local influences on the PG at Al Ain are strongly apparent and the daily variation in PG was found to fall into two main categories: 1) convection dominated, 2) sea breeze dominated.&#160;&#160; On the convection dominated days the PG followed the daily variation in temperature and wind speed closely, with very large maximum values of PG up to 4 kV/m in the mid afternoon.&#160; The other regular daily feature in Al Ain PG was a sharp positive increase in PG up to several kV/m around 1800-1900 local time.&#160; This feature is associated with the arrival of a sea breeze front, which originates more than 150&#160;km away on the Abu Dhabi coastline.&#160; The extremely large change in PG over a very short time scale (tens of minutes) is thought to be due to the action of dust pickup within the sea breeze front as it travels substantial distances over the flat arid landscape.&#160; Overall, the electrical environment at Al Ain is found to be generally very highly charged and so the local effects (primarily from dust and aerosol) mask Global Electric Circuit influences in the surface data.&#160;&#160;&#160;

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Relating Satellite-Observed Cloud Properties from MODIS to Meteorological Conditions for Marine Boundary Layer Clouds

Journal of Climate ◽

10.1175/2009jcli2897.1 ◽

2010 ◽

Vol 23 (6) ◽

pp. 1374-1391 ◽

Cited By ~ 14

Author(s):

Guang J. Zhang ◽

Andrew M. Vogelmann ◽

Michael P. Jensen ◽

William D. Collins ◽

Edward P. Luke

Keyword(s):

Boundary Layer ◽

Meteorological Parameters ◽

Marine Boundary Layer ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Liquid Water Path ◽

Near Surface ◽

Cloud Properties ◽

Lower Tropospheric Stability

Abstract This study examines 6 yr of cloud properties observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the NASA Terra satellite in five prominent marine boundary layer (MBL) cloud regions (California, Peru, Canary, Angola, and Australia) and investigates their relationships with near-surface meteorological parameters obtained from NCEP reanalyses. About 62 000 independent scenes are used to examine the instantaneous relationships between cloud properties and meteorological parameters that may be used for global climate model (GCM) diagnostics and parameterization. Cloud liquid water path (LWP) generally increases with lower-tropospheric stability (LTS) and lifting condensation level (LCL), whereas cloud drizzle frequency is favored by weak LTS and negligible cold air advection. Cloud fraction (CF) depends strongly on variations in LTS, and to a lesser extent on surface air temperature advection and LCL, although the relationships vary from region to region. The authors propose capturing the effects of these three parameters on CF via their linear combination in terms of a single parameter, the effective lower-tropospheric stability (eLTS). Results indicate that eLTS offers a marked improvement over LTS alone in explaining the median CF variations within the different study regions. A parameterization of CF in terms of eLTS is provided, which produces results that are improved over those of Klein and Hartmann’s LTS-only parameterization. However, the new parameterization may not predict the observed variability correctly, and the authors propose a method that might address this shortcoming via a statistical approach.

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