Speakers
Description
Snow accumulation at the South Pole gradually changes the effective depth of in-ice radio detectors. For the Askaryan Radio Array (ARA), this directly affects antenna geometry, thermal noise conditions, and the firn profile used in ray tracing. If not tracked, these changes introduce biases in reconstruction and long term calibration.
We present a data driven method to infer burial rates using seasonal temperature cycles recorded by the DDA and TDA electronics. The annual temperature modulation is modeled as a damped sinusoid, and the phase delay of the seasonal peak is used as a depth proxy. For ARA Station 1, the measured phase depth relation corresponds to an accumulation rate of approximately 19-23 cm/yr, consistent with independent firn temperature measurements from USP50 and other measurements. The exponential decrease of seasonal amplitude with depth is also consistent with thermal diffusion in polar firn. Tracking the shift of the seasonal temperature peak over multiple years shows a cumulative burial increase of roughly 1.5-2 m over about a decade. This measurement is obtained directly from DAQ housekeeping data and does not require repeated physical surveys.
Applying the same method across sparsely deployed stations will allow comparison of local accumulation rates. In addition, long term temperature trends provide a monitor of detector health. Deviations from the expected seasonal behavior can indicate changes in thermal coupling, cable strain, or electronics stability.
This technique is broadly applicable to current and future radio neutrino experiments. As arrays grow larger and more sparsely distributed, continuous in situ monitoring of burial rates will be essential for maintaining reconstruction accuracy, validating ice models, and ensuring long term detector reliability.