TITLE:
Statistical Tests of the Validation of TCO Satellite Measurements, Recorded Simultaneously by TOMS-OMI (2005) and OMI-OMPS (2012-2018)
AUTHORS:
Molina-Almaraz Mario, Pinedo-Vega Jose Luis, Ríos-Martínez Carlos, Mireles-García Fernando
KEYWORDS:
TOMS-OMI and OMPS Data, Global Statistical Validation, Total Column Ozone, Mann-Whitney Test
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.13 No.2,
April
10,
2023
ABSTRACT: Two statistical validation methods were
used to evaluate the confidence level of the Total Column Ozone (TCO) measurements
recorded by satellite systems measuring simultaneously, one using the normal distribution
and another using the Mann-Whitney test. First, the reliability of the TCO measurements
was studied hemispherically. While similar coincidences and levels of significance
> 0.05 were found with the two statistical tests, an enormous variability in
the levels of significance throughout the year was also exposed. Then, using the
same statistical comparison methods, a latitudinal study was carried out in order
to elucidate the geographical distribution that gave rise to this variability. Our
study reveals that between the TOMS and OMI measurements in 2005 there was only
a coincidence in 50% of the latitudes, which explained the variability. This implies
that for 2005, the TOMS measurements are not completely reliable, except between
the -50° and -15° latitude band in the southern
hemisphere and between +15° and +50° latitude band in the northern hemisphere. In
the case of OMI-OMPS, we observe that between 2011 and 2016 the measurements of
both satellite systems are reasonably similar with a confidence level higher than
95%. However, in 2017 a band with a width of 20° latitude centered on the equator appeared, in which the significance levels
were much less than 0.05, indicating that one of the measurement systems had begun
to fail. In 2018, the fault was not only located in the equator, but was also replicated
in various bands in the Southern Hemisphere. We interpret this as evidence of irreversible
failure in one of the measurement systems.