# Atmospheric Electricity Measurements in the Pacific Northwest, Russia
## 3 Observed Effects and Main Results
PG measurements performed on cloudless days [11] showed its increase by two to three times after sunrise. At the same time, the electrical conductivity of the atmosphere increased by only 20% compared with the corresponding values before sunrise. This effect is explained by the action of a convective generator [12]. In the morning, convective and turbulent processes increase, the second and third terms in Formula (2). This leads to an increase in the electrical conduction current and an increase in PG. A comparison was made of the main characteristics of the sunrise effect in the diurnal PG variations obtained at Paratunka Observatory with the results of other authors. It turned out to be a good match [13]. An experiment was conducted at the observatory to directly confirm the presence of a convective generator in the global electrical circuit [14]. For this, in addition to PG observations, we used simultaneous records of the electrical  
Figure 8: Wind effect for 14 December 2021: (**a**) PG values; (**b**) wind speed; (**c**) air conductivity; (**d**) air humidity. conductivity of the atmosphere, as well as its temperature near the earth's surface and at a height of 25 m (Figure 9). Local time is 12 h ahead of world time, LT = UTC+12. Sunrise began at 20:00 UTC (8:00 LT). At this time, PG increased (Figure 9a). At the same time, the air temperature difference at heights of 3 and 25 m increased (Figure 9c). An increase in the vertical temperature gradient increases convective processes. The electrical conductivity of the air decreased both in the morning and in the evening (Figure 9b). The relationship between PG variations and the temperature difference is most closely manifested at sunrise with a correlation coefficient of \(\sim\)0.6 \(\pm\) 0.1 [14]. The appearance of the evening and morning maximum in the daily variation of PG in fair weather conditions does not correlate with meteorological phenomena: humidity, wind strength and direction, precipitation, or cloudiness. The sunrise effect also manifests itself in the spectral characteristics of the electric field. At sunrise, in the PG power spectra in the surface atmosphere in Kamchatka, an increase in the intensity of oscillations was found in the band of periods of 2-2.5 h [15]. Negative PG anomalies before seismic earthquake (EQ) events are a fairly well-known precursor of earthquakes. Such anomalies began to be determined after the appearance of instruments capable of detecting signs of anomalies in PG. For example, one of the early studies of anomalies before EQ with fixation of the PG sign was done in Japan [16]. A review of publications on this issue was made in [17]. The negative anomaly in PG before the earthquake on 27 July 2022, Ms = 4.5 \(\varphi=53.26^{\circ}\) N; \(\lambda=160.73^{\circ}\) E, distance 168.2 km is shown in Figure 10.  
Figure 9: Sunrise effect for 6 November 2007: (**a**) PG values; (**b**) air conductivity; (**c**) air temperature difference at 3 and 25 m.  
A statistical analysis was made of the appearance of negative anomalies before earthquakes in fair weather conditions. A seismic event was considered to be a situation when, in the time interval 24 h after the anomaly, one or several EQs of class K from 11 to 15 (\(M\)s \(\cong\) 4.7-6.7) occurred with epicenters in the area with coordinates (45-55)\({}^{\circ}\) N, (155-165)\({}^{\circ}\) E, including registration point PG. For the period from 1 January 1997 to 31 December 2002 (i.e., for 2189 days) 103 cases of anomalous behavior of the PG component were detected. In 37 (36%) cases, earthquakes occurred after the anomaly in 1-24 h [17]. The seismic regime in the specified area during this period was such that the number of random EQs of class higher than 11 would be 19. Thus, the excess over the random value was 37/19 = 1.9 times. This forecasting method strongly depends on the meteorological situation at the observation point. During rain, snow, fog, strong wind, or overcast, the PG signal is many times higher than the signal from earthquake precursors.