Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Acoustic noise in deep ice and environmental conditions at the South
  Pole   To study the acoustic properties of the Antarctic ice the South Pole Acoustic
Test Setup (SPATS) was installed in the upper part of drill holes for the
IceCube neutrino observatory. An important parameter for the design of a future
acoustic neutrino telescope is the acoustic background noise in the ice and its
spatial and temporal variations. We study the absolute noise level depth
profile from SPATS data and discuss systematic uncertainties. The measured
noise is very stable over one year of data taking, and we estimate the absolute
noise level to be < 10 mPa in the frequency range from 10 kHz to 50 kHz at
depths below 200 m. This noise level is of the same order of magnitude as
observed by ocean based acoustic neutrino detection projects in good weather
conditions.

37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg