Atmospheric Temperature Effect in Secondary Cosmic Rays Observed With a 2 m² Ground‐Based tRPC Detector

Abstract

A high time resolution 2 m 2 tracking detector, based on timing Resistive Plate Chamber (tRPC) cells, has been installed at the Faculty of Physics of the University of Santiago de Compostela (Spain) in order to improve our understanding of the cosmic rays arriving at the Earth's surface. Following a short commissioning of the detector, a study of the atmospheric temperature effect of the secondary cosmic ray component was carried out. To take into account this effect, temperature coefficients, W T (h), were obtained from cosmic ray data using a method based on Principal Component Analysis (PCA). The results obtained show good agreement with the theoretical expectation. The method successfully removes the correlation present between the different atmospheric layers, which would be dominant otherwise. We briefly describe the initial calibration and pressure correction procedures, essential to isolate the temperature effect. Overall, the measured cosmic ray rate displays the expected anticorrelation with the effective atmospheric temperature, through the coefficient α T = −0.279±0.051%/K. Rates follow the seasonal variations, and unusual short-term events are clearly identified too.

Revisiting the Limits of Atmospheric Temperature Retrieval From Cosmic‐Ray Measurements

“…Temperatures between 1,000 and 300 hPa are in this way reasonably well estimated from hard muon rates (RMSE ∼ 3 K), however, accuracy is lost in the tropopause and stratosphere (Figure 3a, dashed‐blue line). Since the soft muon component at ground ( E < 0.4 GeV) is much more affected by the temperature of the lower layers of the atmosphere (Figure 1, continuous red line), it becomes more precise as a temperature estimator below 300 hPa (Figure 3a, dotted‐red line) by suppresing the negative correlation between troposphere and tropopause regions (e.g., Riádigos et al., 2020). The combination of both components gives a marginal improvement at this point (black line).…”

“…They all offer affordable ways to cover large areas at high angular resolution. As an example, the effective atmospheric temperature has been recently measured at ground with a 2 m 2 timing RPC station in (Riádigos et al., 2020), the first time that this technology, capable of time resolutions down to 50–60 ps and precise angular reconstruction on areas of several m 2 (Blanco et al., 2020; Watanabe et al., 2019), has been used for the task. In view of these powerful technological assets, the existence of new detailed calculations of the atmospheric weights, as well as the latest generation of accurate temperature data from the European Centre for Medium‐Range Weather Forecast (ECMWF), reassessing the technological potential of cosmic rays for atmospheric temperature forecast seems very timely if not imperative.…”

Influence of Solar Wind on Secondary Cosmic Rays and Atmospheric Electricity

“…We note that the counts were corrected to the local ambient pressure. However, we cannot exclude that a pressure or temperature profile in the atmosphere above the SEVAN and the NM could modulate the recorded counts (Riádigos et al, 2020). A potential influence of some other, unconsidered parameters of the solar and geomagnetic activity and of the atmospheric state can also not be excluded.…”

Principal Component Analysis of Ground Level Enhancement of Cosmic Ray Events

“…They were able to distinguish three PCs and how they affected PM10 in the four seasons of the year. Riadigos et al (2020) applied PCA methods to the CR data of a newly installed muon detector to remove the atmospheric temperature effect on the data. The PC regression they applied captured at least 77% of the variability in the data due to the effect of the temperature of the air layers at the site of the detector.…”