The Effect of the Solar Eclipse of March 29, 2006 on Atmospheric Pressure Fluctuations and Surface Temperature Profiles

Abstract

The data of measurements of atmospheric pressure fluctuations together with measurements of air temperature profiles in the surface layer of the atmosphere during the total solar eclipse on March 29, 2006 in Kislovodsk on the central line of the shadow are presented. The total phase of the eclipse began at 15:15 local time and lasted 2 min 32 s. According to the measurements of temperature profiles, the fluctuations of the atmospheric pressure difference at the level of the Earth’s surface and at a certain height to which the temperature profiles were measured were restored. The recovered fluctuations were compared with atmospheric pressure fluctuations recorded by a microbarograph, as well as with pressure fluctuations during the solar eclipse in Tynda, in the Amur region, on July 31, 1981. It is shown for the first time that temporary changes in vertical profiles of air temperature in the surface layer of the atmosphere caused by a solar eclipse make the main contribution to the pulsation of atmospheric pressure at ground level.

APPENDIX A

The relationship between surface pressure drop in the lower atmosphere and surface temperature profile

In a state of the atmosphere close to quasi-static equilibrium, the pressure $p(z,x,y,t)$ and atmospheric density $\rho (z,x,y,t)$ are connected by the equation of statics

$$\frac{{dp}}{{dz}} = - g\rho ,$$

(1A)

for arbitrary vertical with horizontal coordinates $x,y$. In the last equation, the density can be expressed in terms of pressure and temperature $T(z,x,y,t)$ using the equation of state $\rho = p{\text{/}}(RT)$. Then, dividing both sides of equation (1) by $p$ and integrating over $z$ from the surface of the earth $z = 0$, where is the pressure $p(z = 0,t) \equiv {{p}_{0}}(t)$, up to some height $z = h$, on which the pressure $p(z = h,t) \equiv p(h,t)$, we obtain the barometric formula for pressure

$$p(h,t) = {{p}_{0}}(t)exp\left( { - \int\limits_0^h {{{dz} \mathord{\left/ {\vphantom {{dz} H}} \right. \kern-0em} H}} (z,t)} \right),$$

(2A)

where $H(z,t) = RT{\text{/}}g$ is the height of a homogeneous atmosphere (we omitted the dependence on $x,y$ everywhere, while implying it).

We consider the lower layer of the atmosphere with a height h $\ll$ H. This condition is always met for h less than 1 km, because the homogeneous atmospheric height H is approximately 8 km. Then, the exponent in (2) is close to 1, so it can be expanded into a series in terms of the small parameter h/H $\ll$ 1 and, up to the first term of the expansion, we can represent (2) in the form $p(h,t) \approx {{p}_{0}}(t)\left( {1 - \int_0^h {dz{\text{/}}H(z,t)} } \right)$, from which we obtain the expression for the weight of the air column $\int_0^h {g\rho (z,t)dz}$ of height h:

$$\begin{gathered} {{p}_{0}}(t) - p(h,t) = \int\limits_0^h {g\rho (z,t)dz} \\ \approx {{p}_{0}}(t)\int\limits_0^h {dz} \frac{1}{{H(z,t)}} = {{p}_{0}}(t)\int\limits_0^h {dz} \frac{g}{{RT(z,t)}}. \\ \end{gathered} $$

(3A)