Atmospheric data assimilation. Primary areas of research interest include: methods of data assimilation, proper use of new satellite and radar observations, and data impact on numerical weather prediction. Observations assimilated include ground-based GPS precipitable water and total zenith delay, spaced-based GPS occultation measurements of bending angle and refractivity, precipitation from raingage, satellite and radar, TOMS ozone, GOES-8 and SSM/I brightness temperature, QSCAT surface wind, SSM/I microwave brightness temperature, and radar reflectivity and radial wind. Predictions include hurricanes, cyclones, squall lines, and summer convection.
Selected Publications
Zou, X., and Q. Xiao, 1999: Studies on the initialization and
simulation of a mature hurricane using a variational bogus data
assimilation scheme. Journal of Atmospheric Science, 57, 836-860.
Zou, X., Q. Xiao, Alan E. Lipton, and George D. Modica, 2001:
A numerical study of the effect of GOES sounder cloud-cleared
brightness temperatures on the prediction of hurricane Felix.
Journal of Applied Meteorology, 40, 34-55.
Zou, X., F. Vandenberghe, B. Wang, M. E. Gorbunov, Y.-H. Kuo,
S. Sokolovskiy, J. C. Chang, J. G. Sela, and R. Anthes, 1999:
A raytracing operator and its adjoint for the use of GPS/MET
refraction angle measurements. Journal Geophysical Research,
Atmospheres, 104, 22,301-22,318.
Zou, X., F. Vandenberghe, B. Wang, M. E. Gorbunov, Y.-H. Kuo,
S. Sokolovskiy, J. C. Chang, J. G. Sela, and R. Anthes, 1999:
A raytracing operator and its adjoint for the use of GPS/MET
refraction angle measurements. Journal Geophysical Research,
Atmospheres, 104, 22,301-22,318.
Zou, X., B. Wang, H. Liu, R. A. Anthes, T. Matsumura, and
Y.-J. Zhu, 2000: Use of GPS/MET refraction angles in 3D variational
analysis. Quarterly Journal Royal Meteorological Society, 126,
3013-3040.
Liu, H., X. Zou, R. A. Anthes, J. C. Chang, J.-H. Tseng, and B. Wang,
2001: The Impact of 837 GPS/MET bending angle profiles
on assimilation and forecasts for the period June 20-30, 1995,
Journal Geophysical Research, 106, 31771-31786.
Zou, X., H. Liu, and R. A. Anthes, 2002: A statistical estimate
of errors in the calculation of radio occultation bending angles
caused by a 2D approximation of raytracing and the assumption of
spherical symmetry of the atmosphere. Journal of Atmospheric and
Oceanic Technology, 19, 51-64.
Zou, X., H. Liu, J. Derber, J. G. Sela, R. Treaton, I. M. Navon,
and B. Wang, 2001: Four-dimensional variational data assimilation
with a full-physics version of the NCEP spectral model: System
development and preliminary results. Quarterly Journal Royal
Meteorological Society, 127, 1095-1122.
Liu, H. and X. Zou, 2001: The impact of NORPEX targeted dropsondes
on the 2-3 day forecasts of a landfalling Pacific winter storm using
NCEP 3D-Var and 4D-Var systems. Monthly Weather Review, 129, 1987-2004.
Zou, X., K. Sriskandarajah, Q.-N. Xiao, W. Yu, and S.-Q. Zhang, 2001:
A note on eliminating finite-amplitude non-physical oscillations from
the solution of an adjoint of finite-difference model. Tellus, 53A,
578-584.
Zhang, S., X. Zou, J. Alquist, I. M. Navon, and J. G. Sela, 2000:
Use of differentiable and nondifferentiable optimization algorithms
for variational data assimilation with discontinuous cost functions.
Monthly Weather Review, 128, 4031-4044.
