Diurnal pressure variations in the Garhwal Himalaya: atmospheric fluctuations associated with the solid Earth tide

Abstract

Air pressure measurements conducted over 5 years at the Garhwal Himalaya (1836 m amsl) in India show (expected) seasonal variations, along with marked diurnal and semi‐diurnal fluctuations. Measurements were carried out at 15‐min intervals at two sites within ~1 km of each other. Mean monthly air pressure is lowest during summer (June/July) and highest during winter (October–January), with an annual variation of ~10 hPa. The diurnal variation is ~2 hPa, with two minima and two maxima. The pressure minima are usually observed in the evening, between 1600 and 1700 Indian Standard Time (ist) (1030 and 1130 utc) and during the early hours, between 0400 and 0500 ist. The maximum values are observed in the morning, between 1000 and 1100 ist, and at night, between 2200 and 2300 ist. These daily variations are attributed to diurnal and semidiurnal tidal effects, which are well correlated with gravitational variations of ~0.8μgal observed at the same location using a superconducting gravimeter.

Analyzing Atmospheric Pressure Variations in Time and Height: a Didactic Proposal Employing a Smartphone Barometer

“…To proceed with the validation, atmospheric pressure was continuously measured for 48 hours, starting from 0h00 on the day February 13, 2021, and ending at 23h59 on February 14, 2021. As we have described, we remind the reader that the atmospheric pressure presents a daily cyclic behavior, with an approximate 12-hour period [48].…”