Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the size distribution of sunspot groups in the Greenwich sunspot
  record 1874-1976   We investigate the size distribution of the maximum areas and the
instantaneous distribution of areas of sunspot groups using the Greenwich
sunspot group record spanning the interval 1874-1976. Both distributions are
found to be well described by log-normal functions. Using a simple model we can
transform the maximum area distribution into the instantaneous area
distribution if the sunspot area decay rates are also distributed log-normally.
For single-valued decay rates the resulting snapshot distribution is
incompatible with the observations. The current analysis therefore supports the
results of Howard (1992) and MartinezPillet (1993). It is not possible to
distinguish between a linear and a quadratic decay law, however, with the
employed data set.

21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
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The categories of this paper are: stat
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc