An improved global zenith tropospheric delay model GZTD2 considering diurnal variations

Abstract. The zenith tropospheric delay (ZTD) is an important atmospheric parameter in the wide application of global navigation satellite systems (GNSS) technology in geoscience. Given that the temporal resolution of the current global zenith tropospheric delay model (GZTD) is only 24 h, an improved model, GZTD2, has been developed by taking the diurnal variations into consideration and modifying the model expansion function. The data set used to establish this model is the global ZTD grid data provided by Global Geodetic Observing System (GGOS) Atmosphere spanning from 2002 to 2009. We validated the proposed model with respect to ZTD grid data from GGOS Atmosphere, which was not involved in modeling, as well as International GNSS Service (IGS) tropospheric product. The obtained results of ZTD grid data show that the global average bias and root mean square (rms) for the GZTD2 model are 0.2 and 3.8 cm, respectively. The global average bias is comparable to that of the GZTD model, but the global average rms is improved by 3 mm. The bias and rms are far better than the EGNOS model and the UNB series models. The testing results from global IGS tropospheric product show the bias and rms (−0.3 and 3.9 cm) of the GZTD2 model are superior to that of GZTD (−0.3 and 4.2 cm), suggesting higher accuracy and reliability compared to the EGNOS model, as well as the UNB series models.

[1]  H. Black.  An easily implemented algorithm for the tropospheric range correction , 1978 .

[2]  Richard B. Langley,et al.  The residual tropospheric propagation delay: How bad can it get? , 1998 .

[3]  Robert Weber,et al.  Development of an improved empirical model for slant delays in the troposphere (GPT2w) , 2015, GPS Solutions.

[4]  T. Nilsson,et al.  GPT2: Empirical slant delay model for radio space geodetic techniques , 2013, Geophysical research letters.

[5]  A. Sterl,et al.  The ERA‐40 re‐analysis , 2005 .

[6]  Kevin E. Trenberth,et al.  Trends and variability in column-integrated atmospheric water vapor , 2005 .

[7]  H. Schuh,et al.  Short Note: A global model of pressure and temperature for geodetic applications , 2007 .

[8]  Robert Weber,et al.  Improved Troposphere Blind Models Based on Numerical Weather Data , 2013 .

[9]  Alan Dodson,et al.  Assessment of EGNOS Tropospheric Correction Model , 1999 .

[10]  H. S. Hopfield.  Two- quartic tropospheric refractivity profile for correcting satellite data , 1969 .

[11]  Yao Yi.  A new global zenith tropospheric delay model GZTD , 2013 .

[12]  Sung H. Byun,et al.  A new type of troposphere zenith path delay product of the international GNSS service , 2009 .

[13]  Gunnar Elgered,et al.  Sensing of diurnal and semi‐diurnal variability in the water vapour content in the tropics using GPS measurements , 2007 .

[14]  Torben Schüler,et al.  The TropGrid2 standard tropospheric correction model , 2013, GPS Solutions.

[15]  Wei Li,et al.  A new global zenith tropospheric delay model IGGtrop for GNSS applications , 2012 .

[16]  H. Schuh,et al.  Atmospheric Effects in Space Geodesy , 2013 .

[17]  Richard B. Langley,et al.  Assessment of Atmospheric Delay Correction Models for the Japanese MSAS , 2001 .

[18]  Yuei-An Liou,et al.  New versions of the BDS/GNSS zenith tropospheric delay model IGGtrop , 2014, Journal of Geodesy.

[19]  James J. Spilker,et al.  GPS Signal Structure and Performance Characteristics , 1978 .

[20]  J. Saastamoinen.  Contributions to the theory of atmospheric refraction , 1972 .

[21]  R. Langley,et al.  UNB Neutral Atmosphere Models : Development and Performance , 2006 .

[22]  T. Pany,et al.  The european satellite navigation system Galileo , 2008, Wuhan University Journal of Natural Sciences.

[23]  Shuanggen Jin,et al.  Seasonal variability of GPS‐derived zenith tropospheric delay (1994–2006) and climate implications , 2007 .

[24]  Shuanggen Jin,et al.  Characterization of diurnal cycles in ZTD from a decade of global GPS observations , 2009 .

[25]  Richard B. Langley,et al.  UNB3m_pack: a neutral atmosphere delay package for radiometric space techniques , 2008 .