In this paper, atmospheric profiles of refractivity, pressure and temperature derived from the Constellation Observing
System for Meteorology, Ionosphere and Climate (COSMIC) radio occultation (RO) mission are compared statistically
with collocated high-vertical-resolution soundings of 38 radiosonde stations distributed over Australia and the Antarctica
during the period from July 15, 2006 to April 30, 2008.
Refractivity comparison results show that through 0~30 km, the mean absolute fractional refractivity differences are less
than 0.5%, but the refractivity standard deviations vary greatly. The smallest refractivity standard deviation of less than
1% is got at about 10km and the largest standard deviations are found below 5km. It is shown in the pressure comparison
results that the mean absolute fractional pressure differences are generally less than 0.5% between 5 km and 25 km.
Below 5 km, the mean absolute fractional pressure differences increase to be about 2%. Temperature comparison results
show that the mean absolute temperature differences are generally less than 1K and the standard deviations generally less
than 2K in the middle to upper atmosphere. In the lower troposphere, the temperature standard deviation increases to be
larger than 2.5K.
It can be concluded that the precision of GPS RO data from COSMIC are equivalent to radiosonde data in the upper
troposphere and lower stratosphere. Being able to complement radiosonde network over the oceans and polar regions,
GPS RO data are of great value for climate monitoring.