Ir. C.M.H. (Christine) Unal
Christine is researcher in atmospheric radar remote sensing. Her research interests are weather/atmospheric radar signal processing, radar Doppler-polarimetry, rain microphysics and atmospheric dynamic retrievals. She is responsible for the MSc course Atmospheric Observation (CIE4608) at the faculty Civil Engineering and Geosciences. Further she teaches on the MSc course Microwave Radar and Remote Sensing (ET4169) at the faculty Electrical Engineering. She obtained in France the master of Physics (Nice, 1986) and the D.E.A in Physics for Remote Sensing (Paris, 1987). After a short experience in the industry, she joined the faculty Electrical Engineering in Delft in 1988 where she developed in the field of radar polarimetry.
Weather radars can measure the movement of particles, raindrops, snow, ice particles, in the atmosphere. These particles, termed hydrometeors, contain water in different phases, liquid and ice. In the European network (“Buienradar Europa”) most of the radars are not polarimetric. However polarimetry provides information on the shape of the hydrometeors, which can be used for particles classification. Combining simultaneously Doppler and polarimetric measurements (radar Doppler polarimetry) leads on one hand to enhanced techniques for retrieving microphysical and dynamical properties of the hydrometeors (rain microphysics and atmospheric dynamic retrievals), and on the other hand to new signal processing methods to improve the accuracy of the measurands (weather/atmospheric radar signal processing). For example, non-atmospheric echoes can be more efficiently discarded. Concerning the research for new retrieval techniques, one cannot focus on a microphysical property of the medium, particle size distribution for example, without thorough knowledge about the involved dynamics (wind, turbulence) and vice versa. Creating new retrieval techniques exploiting this duality is currently her key research. Christine uses the TU-Delft Doppler-polarimetric radar, TARA, located at Cabauw to experiment in the fields of signal processing and retrieval technique.
- Unal, C., 2015: High-resolution raindrop size distribution retrieval based on the Doppler spectrum in the case of slant profiling radar. J. Atmos. Oceanic Technol., 32, 1191-1208, doi: 10.1175/JTECH-D-13-00225.1
- Unal, C., 2009: Spectral polarimetric radar clutter suppression to enhance atmospheric echoes. J. Atmos. Oceanic Technol., 26, 1781-1797, doi: 10.1175/2009/JTECHA1170.1
- Spek, A. L. J., C. M. H. Unal, D. N. Moisseev, H. W. J. Russchenberg, V. Chandrasekar, and Y. Dufournet, 2008: A new technique to categorize and retrieve the microphysical properties of ice particles above the melting layer using radar dual-polarization spectral analysis. J. Atmos. Oceanic Technol., 25, 482-497, doi: 10.1175/2007/JTECHA944
- Moisseev, D. N., V. Chandrasekar, C. M. H. Unal, and H. W. J. Russchenberg, 2006: Dual-polarization spectral analysis for retrieval of effective raindrop shapes. J. Atmos. Oceanic Technol., 23, 1682-1695, doi:10.1175/JTECH1945.1
- Yanovsky F. J., H. W. J. Russchenberg, and C. M. H. Unal, 2005: Retrieval of information about turbulence in rain by using Doppler-polarimetric radar. IEEE Trans. Microwave theory and techniques, 53, 444-450.
- Unal, C. M. H., and D. N. Moisseev, 2004: Combined Doppler and polarimetric radar measurements: correction for spectrum aliasing and nonsimultaneous polarimetric measurements. J. Atmos. Oceanic Technol., 21, 443-456, doi:10.1175/1520-0426(2004)021<0443:CDAPRM>2.0.CO;2
- Moisseev D. N., C. M. H. Unal, H. W. J. Russchenberg, and L. P. Ligthart, 2002: Improved polarimetric calibration for atmospheric radars. J. Atmos. Oceanic Technol., 19, 1968-1977.
- Moisseev D. N., C. M. H. Unal, H. W. J. Russchenberg, and L. P. Ligthart, 2002: A new method to separate ground clutter and atmospheric reflections in the case of similar Doppler velocities. IEEE Trans. Geosci. Remote Sens., 40(2), 239-246.
- Unal, C. M. H., R. J. Niemeijer, J. S. van Sinttruyen, and L. P. Ligthart, 1994: Calibration of a polarimetric radar using a rotatable dihedral corner reflector. IEEE Trans. Geosci. Remote Sens., 32(4), 837-845
- Unal, C. M. H., P. Snoeij, and P.J.F. Swart, 1991: The polarization-dependent relation between radar backscatter from the ocean surface and surface wind vector at frequencies between 1 and 18 GHz. IEEE Trans. Geosci. Remote Sens., 29(4), 621-626
- MSc course Atmospheric Observation (CIE4608): course manager and lecturer
- MSc course Microwave Radar and Remote Sensing (ET4169): lecturer