Validation of COSMIC ionospheric peak parameters by the measurements of an ionosonde chain in China

L Hu,B Wu,S Chang,G Li,L Liu,Z Wu,B Zhao,X Hao,B Ning,Z Huang

doi:10.5194/angeo-32-1311-2014

Abstract

Abstract. Although the electron density profiles (EDPs) from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) measurement have been validated by ionosonde data at a number of locations during the solar minimum period, the performance of COSMIC measurements at different latitudes has not been well evaluated, particularly during the solar maximum period. In this paper the COSMIC ionospheric peak parameters (peak electron density of the F region – NmF2; peak height of the F region – hmF2) are validated by the ionosonde data from an observation chain in China during the solar maximum period of 2011–2013. The validations show that the COSMIC measurement generally agrees well with the ionosonde observation. The error in NmF2 from COSMIC and ionosonde measurements varies with latitude. At midlatitude stations, the differences between COSMIC NmF2s and those of ionosondes are very slight. However, COSMIC NmF2 overestimates (underestimates) that of the ionosonde at the north (south) of the equatorial ionization anomaly (EIA) crest. The relative errors of hmF2s are much lower than those of NmF2s at all stations, which indicates the EDP retrieval algorithm of the COSMIC measurement has a better performance in determining the ionospheric peak height. The root mean square errors (RMSEs) of NmF2s (hmF2s) are higher (lower) during the daytime than during the nighttime at all stations. Correlation analysis shows that the correlations for both NmF2s and hmF2s are comparably good (correlation coefficients > 0.9) at midlatitude stations, while correlations of NmF2 (correlation coefficients > 0.9) are higher than those of hmF2 (correlation coefficients > 0.8) at low-latitude stations.

Highlights

Since the radio occultation (RO) technique using the GPS signals was first employed by the Global Positioning System Meteorology (GPS/MET) experiment aboard the Microlab1 satellite in 1995, the low-earth-orbit-based GPS RO technique has proven successful in exploring the earth’s lower atmosphere and ionosphere
The result indicates that the COSMIC NmF2 and hmF2 generally follow the same trends of diurnal variation as those of the ionosondes at four stations
The COSMIC ionospheric peak parameters (NmF2 and hmF2) over China are validated by the ionosonde data from an observation chain which consists of four stations during 2011–2013

Summary

Introduction

Since the radio occultation (RO) technique using the GPS signals was first employed by the Global Positioning System Meteorology (GPS/MET) experiment aboard the Microlab satellite in 1995, the low-earth-orbit-based GPS RO technique has proven successful in exploring the earth’s lower atmosphere and ionosphere. The RO data provide vertical profiles of neutral density, temperature, pressure and water vapor in the stratosphere and troposphere and electron density in the ionosphere (Hajj and Romans, 1998; Rocken et al, 2000; Schreiner et al, 1999), and they have been widely used in atmosphere and ionosphere research, as well as weather and space weather forecasting (Krankowski et al, 2011; Wickert et al, 2009). A constellation of six microsatellites, termed the FORMOSAT-3/COSMIC (Formasa Satellite 3 – Constellation Observing System for Meteorology, Ionosphere, and Climate) was launched into a low earth orbit at around 800 km in 2006. 2008, 2009, 2010, 2011), storm time ionospheric behavior (Zakharenkova et al, 2012) and low-latitude F3 layer occurrence (Zhao et al, 2011)

Results

Discussion

Conclusion