Study of fair weather surface atmospheric electric field at high altitude station in Eastern Himalayas

Abstract Fair weather atmospheric electric field has been studied at Darjeeling (latitude 27001′N longitude 88036′E, 2200 masl), a high altitude station in eastern Himalayas and compared with the Carnegie curve. The potential gradient (PG) measured is larger than Carnegie curve for most of the time of the day. In order to understand the effect of the local components we have studied the PG variation along with the meteorological parameters and atmospheric constituents such as mixed layer depth, potential temperature, PM2.5, black carbon (BC), aerosol optical depth (AOD), integrated water vapour and liquid water. The local components like PM2.5 and BC show a good correlation with PG. On the other hand Columnar quantities like AOD as well as integrated water vapour and liquid water shows negative correlation with PG which could be associated with the higher mobile negative charges and the complex behavior of space charges. The periodogram of fair weather PG data shows one half day, one day and 100 days periodicity, the power being maximum for one day period. A comparison with other observations shows the presence of larger number of peaks in summer. Morning and evening PG are in general lower compared to the other sites.