Atmospheric electric potential gradient measurements of ash clouds generated by pyroclastic flows at Unzen Volcano, Japan

1996 ◽  
Vol 23 (14) ◽  
pp. 1789-1792 ◽  
Author(s):  
Toshiro Miura ◽  
Takehiro Koyaguchi ◽  
Yoshikazu Tanaka
Keyword(s):  
Electric Potential ◽  
Potential Gradient ◽  
Pyroclastic Flows ◽  
Unzen Volcano ◽  
Gradient Measurements ◽  
Atmospheric Electric Potential Gradient

scholarly journals Revisiting the long-term decreasing trend of atmospheric electric potential gradient measured at Nagycenk, Hungary, Central Europe

2021 ◽  
Vol 39 (4) ◽  
pp. 627-640
Author(s):  
Attila Buzás ◽  
Veronika Barta ◽  
Tamás Horváth ◽  
József Bór
Keyword(s):  
Time Series ◽  
Electric Field ◽  
Central Europe ◽  
Electric Potential ◽  
Potential Gradient ◽  
Time Dependent ◽  
Shielding Effect ◽  
Term Variation ◽  
Atmospheric Electric Potential Gradient

Abstract. In 2003, a decreasing trend was reported in the long-term (1962–2001) fair weather atmospheric electric potential gradient (PG) measured in the Széchenyi István Geophysical Observatory (NCK; 47∘38′ N, 16∘43′ E), Hungary, Central Europe. The origin of this reduction has been the subject of a long-standing debate, due to a group of trees near the measurement site which reached significant height since the measurements have started. Those trees have contributed to the lowering of the ambient vertical electric field due to their electrostatic shielding effect. In the present study, we attempt to reconstruct the true long-term variation of the vertical atmospheric electric field at NCK. The time-dependent shielding effect of trees at the measurement site was calculated to remove the corresponding bias from the recorded time series. A numerical model based on electrostatic theory was set up to take into account the electrostatic shielding of the local environment. The validity of the model was verified by on-site measurement campaigns. The changing height of the trees between 1962 and 2017 was derived from national-average age–height diagrams for each year. Modelling the time-dependent electrical shielding effect of the trees at NCK revealed that local effects played a pivotal role in the long-term decrease. The results suggest that earlier attempts could not quantify the shielding effect of the trees at NCK accurately. In this work it is found that the reconstructed PG time series at NCK exhibits an increase between 1962 and 1997 followed by a decaying trend since 1997. It is pointed out that long-term variation in summertime and wintertime PG averages should be analysed separately as these may contribute to trends in the annual mean values rather differently.

High-Frequency Response of the Atmospheric Electric Potential Gradient Under Strong and Dry Boundary-Layer Convection

2017 ◽  
Vol 166 (1) ◽  
pp. 69-81 ◽  
Author(s):  
Ricardo Conceição ◽  
Hugo Gonçalves Silva ◽  
Alec Bennett ◽  
Rui Salgado ◽  
Daniele Bortoli ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Frequency Response ◽  
Electric Potential ◽  
High Frequency ◽  
Potential Gradient ◽  
High Frequency Response ◽  
Atmospheric Electric Potential Gradient
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