Assimilation of GPS RO Refractivity Data and Its Impact on Simulations of Trade Wind Inversion and a Winter Cold Front


Assimilation of Global Positioning System (GPS) Radio Occultation (RO) refractivity based on WRF-3DVAR is applied to numerical weather predictions (NWP) in Hawaii, where limited conventional observations and poor representation of local circulations in global analysis constrain the quality of numerical weather predictions. For a summer trade wind case, with GPS RO refractivity assimilated, the trade wind inversion is better predicted. For a winter cold front case, the propagation of the cold front is also better simulated when GPS RO refractivity is assimilated. Furthermore, the moist tongue associated with the cold front is better defined and the vertical profiles of temperature and moisture are largely improved when compared to the model run without GPS RO assimilation.

Share and Cite:

Zhou, C. and Chen, Y. (2014) Assimilation of GPS RO Refractivity Data and Its Impact on Simulations of Trade Wind Inversion and a Winter Cold Front. Natural Science, 6, 605-614. doi: 10.4236/ns.2014.68060.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Zhang, Y., Chen, Y.-L., Hong, S.-Y., Juang, H.-M.H. and Kodama, K. (2005) Validation of the Coupled NCEP Mesoscale Spectral Model and an Advanced Land Surface Model over the Hawaiian Islands. Part I: Summer Trade Wind Conditions and a Heavy Rainfall Event. Weather Forecasting, 20, 847-872.
[2] Yang, Y., Chen, Y.-L. and Fujioka, F.M. (2005) Numerical Simulations of the Island-Induced Circulation over the Island of Hawaii during HaRP. Monthly Weather Review, 133, 3693-3713.
[3] Yang, Y., Chen, Y.-L. and Fujioka, F.M. (2008) Effects of Trade Wind Strength and Direction on the Leeside Circulations and Rainfall of the Island of Hawaii. Monthly Weather Review, 136, 4799-4818.
[4] Yang, Y. and Chen, Y.-L. (2008) Effects of Terrain Heights and Sizes on Island-Scale Circulations and Rainfall for the Island of Hawaii during HaRP. Monthly Weather Review, 136, 120-146.
[5] Nguyen, H.V., Chen, Y.-L. and Fujioka, F. (2010) Numerical Simulations of Island Effects on Airflow and Weather during the Summer over the Island of Oahu. Monthly Weather Review, 138, 2253-2280.
[6] Carlis, D.L., Chen, Y.-L. and Morris, V. (2010) Numerical Simulations of Island-Scale Airflow and the Maui Vortex during Summer Trade Wind Conditions. Monthly Weather Review, 138, 2706-2736.
[7] Chen, Y.-L. and Feng, J. (1995) The Influences of Inversion Height on the Precipitation and Airflow over the Island of Hawaii. Monthly Weather Review, 123, 1660-1676.<1660:TIOIHO>2.0.CO;2
[8] Chen, Y.-L. and Feng, J. (2001) Numerical Simulations of Airflow and Cloud Distributions over the Windward Side of the Island of Hawaii. Part I: The Effects of Trade Wind Inversion. Monthly Weather Review, 129, 1117-1134.<1117:NSOAAC>2.0.CO;2
[9] Leopold, L.B. (1949) The Interaction of Trade Wind and Sea Breeze, Hawaii. Journal of Meteorology, 6, 312-320.<0312:TIOTWA>2.0.CO;2
[10] Ao, C.O., Waliser, D.E., Chan, S.-K., Li, J.-L., Tian, B., Xie, F. and Manucci, A.J. (2012) Planetary Boundary Layer Heights from GPS Radio Occultation Refractivity and Humidity Profiles. Journal of Geophysical Research, 117, D16117.
[11] Guo, P., Kuo, Y.-H., Sokolovskiy, S.V. and Lenschow, D.H. (2011) Estimating Atmospheric Boundary Layer Depth Using COSMIC Radio Occultation Data. Journal of the Atmospheric Sciences, 68, 1703-1713.
[12] Xie, F., Wu, D.L., Ao, C.O., Mannucci, A.J. and Kursinski, E.R. (2012) Advances and Limitations of Atmospheric Boundary Layer Observations with GPS Occultation over Southeast Pacific Ocean. Atmospheric Chemistry and Physics, 12, 903-918.
[13] Kuo, Y.-H., Wee, T.K., Sokolovskiy, S., Rocken, C., Schreiner, W., Hunt, D. and Anthes, R.A. (2004) Inversion and Error Estimation of GPS Radio Occultation Data. Journal of the Meteorological Society of Japan, 82B, 507-531.
[14] Kursinski, E.R., Hajj, G.A., Schofield, J.T., Linfield, R.P. and Hardy, K.R. (1997) Observing Earth’s Atmosphere with Radio Occultation Measurements Using the Global Positioning System. Journal of Geophysical Research, 102, 2342923465.
[15] Kuo, Y.-H., Schreiner, W.S., Wang, J., Rossiter, D.L. and Zhang, Y. (2005) Comparison of GPS Radio Occultation Soundings with Radiosondes. Geophysical Research Letters, 32, L05817.
[16] Ho, S.-P., Kuo, Y.-H. and Sokolovskiy, S. (2007) Improvement of the Temperature and Moisture Retrievals in the Lower Troposphere Using AIRS and GPS Radio Occultation Measurements. Journal of Atmospheric and Oceanic Technology, 24, 1726-1739.
[17] Huang, C.-Y., Kuo, Y.-H., Chen, S.-H. and Vandenberghe, F. (2005) Improvements in Typhoon Forecasts with Assimilated GPS Occultation Refractivity. Weather Forecasting, 20, 931-953.
[18] Wee, T.-K., Kuo, Y.-H., Bromwich, D.H. and Monaghan, A.J. (2008) Assimilation of GPS Radio Occultation Refractivity Data from CHAMP and SAC-C Missions over High Southern Latitudes with MM5 4DVAR. Monthly Weather Review, 136, 2923-2944.
[19] Cucurull, L., Derber, J.C. and Treadon, R. and Purser, R.J. (2007) Assimilation of Global Positioning System Radio Occultation Observations into NCEP’s Global Data Assimilation System. Monthly Weather Review, 135, 3174-3193.
[20] Cucurull, L. and Derber, J.C. (2008) Operational Implementation of COSMIC Observations into NCEP’s Global Data Assimilation System. Weather Forecasting, 23, 702-711.
[21] Von Engeln, A., Healy, S., Marquardt, C., Andres, Y. and Sancho, F. (2009) Validation of Operational GRAS Radio Occultation Data. Geophysical Research Letters, 32, L06815.
[22] Anthes, R.A., Rocken, C. and Kuo, Y.-H. (2000) Application of COSMIC to Meteorology and Climate. Terrestrial, Atmospheric and Oceanic Sciences, 11, 115-156.
[23] Anthes, R.A., Ector, D., Hunt, D.C., Kuo, Y.-H., Rocken, C., Schreiner, W.S., Sokolovskiy, S.V., Syndergaard, S., Wee, T.-K., Zeng, Z., Bernhardt, P.A., Dymond, K.F., Chen, Y., Liu, H., Manning, K., Randel, W.J., Trenberth, K.E., Cucurull, L., Healy, S.B., Ho, S.-P., McCormick, C., Meehan, T.K., Thompson, D.C. and Yen, N.L. (2008) The COSMIC/FORMOSAT-3 Mission: Early Results. Bulletin of the American Meteorological Society, 89, 313-333.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.