Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On statistical approaches to generate Level 3 products from satellite
  remote sensing retrievals   Satellite remote sensing of trace gases such as carbon dioxide (CO$_2$) has
increased our ability to observe and understand Earth's climate. However, these
remote sensing data, specifically~Level 2 retrievals, tend to be irregular in
space and time, and hence, spatio-temporal prediction is required to infer
values at any location and time point. Such inferences are not only required to
answer important questions about our climate, but they are also needed for
validating the satellite instrument, since Level 2 retrievals are generally not
co-located with ground-based remote sensing instruments. Here, we discuss
statistical approaches to construct Level 3 products from Level 2 retrievals,
placing particular emphasis on the strengths and potential pitfalls when using
statistical prediction in this context. Following this discussion, we use a
spatio-temporal statistical modelling framework known as fixed rank kriging
(FRK) to obtain global predictions and prediction standard errors of
column-averaged carbon dioxide based on Version 7r and Version 8r retrievals
from the Orbiting Carbon Observatory-2 (OCO-2) satellite. The FRK predictions
allow us to validate statistically the Level 2 retrievals globally even though
the data are at locations and at time points that do not coincide with
validation data. Importantly, the validation takes into account the prediction
uncertainty, which is dependent both on the temporally-varying density of
observations around the ground-based measurement sites and on the
spatio-temporal high-frequency components of the trace gas field that are not
explicitly modelled. Here, for validation of remotely-sensed CO$_2$ data, we
use observations from the Total Carbon Column Observing Network. We demonstrate
that the resulting FRK product based on Version 8r compares better with TCCON
data than that based on Version 7r.

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The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th