| Summary: | Simultaneous dual station observations of the atmospheric electric potential gradient (PG) at Bharati and Maitri studied for the period 2014-2016, bring out a new regional diurnal pattern of fair-weather PG for the coastal Antarctic region, perhaps the ubiquitous characteristics of the PG for the coastal Antarctic region. It is a broad minimum in the Carnegie-type PG variation. The surface wind distorts the fair-weather diurnal pattern of PG over Bharati more significantly than at Maitri. Katabatic wind effect over Bharati PG than Maitri PG is the sharper slope gradient of the ice sheet over Bharati than over Maitri as a consequence the katabatic wind streamlines drain over the Lambert glacier, located close to Bharati station. The wind speed significantly affects the Bipolar Air Ion Concentration (BAIC) by accumulation and dispersion. The concentration is maximum when the wind speed is minimum. Obviously, the PG is minimum during these hours. This particular signature distorts the expected global pattern of the PG at Bharati. Data quality is improved by measuring the PG using the EFM flush mounted with ground EFM rather than from an elevated site. Perhaps this position reduces the wind effects on the PG and favours the detection of globally representative data.
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