We present results of the first time observations of whistlers during day time (sunrise) on 4th January 2017 at 01 UT ($$\hbox {UT} + 5.30 = \hbox {IST}$$) at Indian low latitude ground station Varanasi (geomag. lat. $$14{^{\circ }}55^\prime \hbox {N}$$, geomag. long. $$153{^{\circ }}54^\prime \hbox { E}$$, L.1.078). The main goal of analysis is to study the propagation characteristic of the observed whistlers during the day time (sunrise). These whistlers were observed during the quiet geomagnetic conditions (Dst-index = –8 nT). The dispersions of the observed whistlers are found between 11.16 and $$14.78\hbox { s}^{1/2}$$, which shows that the observed whistlers have propagated in the ducted mode and the whole propagation path of whistlers lies in the ionosphere. Their columnar ionospheric electron contents lie between 23.57 TECU and 39.44 TECU. The ionospheric parameters derived from whistler data at Varanasi compare well with other measurements made by other techniques.

中文翻译：

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在低纬度瓦拉纳西观察到的白天吹口哨（$$L = 1.078$$L=1.078）

我们展示了 2017 年 1 月 4 日 01 UT ($$\hbox {UT} + 5.30 = \hbox {IST}$$) 在印度低纬度地面站瓦拉纳西 ( geomag. lat. $$14{^{\circ }}55^\prime \hbox {N}$$, geomag. long. $$153{^{\circ }}54^\prime \hbox { E}$$, L.1.078）。分析的主要目的是研究观察到的哨声在白天（日出）的传播特性。这些哨声是在安静的地磁条件下观察到的（Dst-index = –8 nT）。观测到的哨声在 11.16 到 $$14.78\hbox { s}^{1/2}$$ 之间，表明观测到的哨声以导管模式传播，整个传播路径位于电离层. 它们的柱状电离层电子含量介于 23.57 TECU 和 39.44 TECU 之间。