Validation of Preliminary Results of Thermal Tropopause Derived from FY-3C GNOS Data

Abstract

The state-of-art global navigation satellite system (GNSS) occultation sounder (GNOS) onboard the FengYun 3 series C satellite (FY-3C) has been in operation for more than five years. The accumulation of FY-3C GNOS atmospheric data makes it ready to be used in atmosphere and climate research fields. This work first introduces FY-3C GNOS into tropopause research and gives the error evaluation results of long-term FY-3C atmosphere profiles. We compare FY-3C results with Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) and radiosonde results and also present the FY-3C global seasonal tropopause patterns. The mean temperature deviation between FY-3C GNOS temperature profiles and COSMIC temperature profiles from January 2014 to December 2017 is globally less than 0.2 K, and the bias of tropopause height (TPH) and tropopause temperature (TPT) annual cycle derived from both collocated pairs are about 80–100 m and 1–2 K, respectively. Also, the correlation coefficients between FY-3C GNOS tropopause parameters and each radiosonde counterpart are generally larger than 0.9 and the corresponding regression coefficients are close to 1. Multiple climate phenomena shown in seasonal patterns coincide with results of other relevant studies. Our results demonstrate the long-term stability of FY-3C GNOS atmosphere profiles and utility of FY-3C GNOS data in the climate research field.

Evaluation of Tropopause Height from Sentinel-6 GNSS Radio Occultation Using Different Methods

“…Additionally, the tropopause serves as the upper limit for the integration of tropospheric parameters in physics and chemistry, including tropospheric temperature [11] and tropospheric column ozone [12]. The TPH can be determined from the use of radiosonde data [7,[13][14][15] or from Global Navigation Satellite System (GNSS) radio occultation (RO) data from different satellites [5,[16][17][18][19][20][21][22][23][24][25].…”

“…be determined from the use of radiosonde data [7,[13][14][15] or from Global Navigation Satellite System (GNSS) radio occultation (RO) data from different satellites [5,[16][17][18][19][20][21][22][23][24][25].…”

“…By examining the temperature profile obtained from the processing of GNSS RO data, the inflection point in the temperature profile was defined as the lapse rate tropopause (LRT) based on the World Metrological Organization (WMO 1957 definition [35]. The LRT method is widely used because it is a simple and easy method to apply to the temperature profile generated from GNSS RO data or radiosondes [20,22,23,36].…”

“…Zhran and Mousa [22] estimated the global TPH using the LRT method from Meteorological Operational Polar Satellite (MetOp) data. Liu et al [23] identified the TPH from the FengYun 3 series C satellite In this study, four different techniques are discussed to determine the TPH from GNSS RO. The TPH was estimated from the lapse rate, cold point, N, and BA.…”

“…Zhran and Mousa [22] estimated the global TPH using the LRT method from Meteorological Operational Polar Satellite (MetOp) data. Liu et al [23] identified the TPH from the FengYun 3 series C satellite (FY-3C) data using the LRT method. Schmidt et al [21] determined the global TPH from the Challenging Minisatellite Payload (CHAMP) satellite data and the U.S.-Argentinian Satelite de Aplicaciones Cientificas-C (SAC-C) data using the LRT method.…”