volume | PIER Journals

Abstract

The influence of atmospheric gases and tropospheric phenomena becomes more relevant at frequencies within the THz band (100 GHz to 10 THz), severely affecting the propagation conditions. The use of radiosoundings in propagation studies is a well established measurement technique in order to collect information about the vertical structure of the atmosphere, from which gaseous and cloud attenuation can be estimated with the use of propagation models. However, some of these prediction models are not suitable to be used under rainy conditions. In the present study, a method to identify the presence of rainy conditions during radiosoundings is introduced, with the aim of filtering out these events from yearly statistics of predicted atmospheric attenuation. The detection procedure is based on the analysis of a set of parameters, some of them extracted from synoptical observations of weather (SYNOP reports) and other derived from radiosonde observations (RAOBs). The performance of the method has been evaluated under different climatic conditions, corresponding to three locations in Spain, where colocated rain gauge data were available. Rain events detected by the method have been compared with those precipitations identified by the rain gauge. The pertinence of the method is discussed on the basis of an analysis of cumulative distributions of total attenuation at 100 and 300 GHz. This study demonstrates that the proposed method can be useful to identify events probably associated to rainy conditions. Hence, it can be considered as a suitable algorithm in order to filter out this kind of events from annual attenuation statistics.

1. Siegel, P. H., "Terahertz technology," IEEE Transactions on Microwave Theory and Techniques, Vol. 50, No. 3, 910-928, 2002.
doi:10.1109/22.989974

2. Tonouchi, M., "Cutting-edge terahertz technology," Nature Photonics, Vol. 1, No. 2, 97-105, 2007.
doi:10.1038/nphoton.2007.3

3. Zhou, H., F. Ding, Y. Jin, and S. He, "Terahertz metamaterial modulators based on absorption," Progress In Electromagnetics Research, Vol. 119, 449-460, 2011.
doi:10.2528/PIER11061304

4. Xu, O., "Diagonal horn gaussian e±ciency enhancement by dielectric loading for submillimeter wave application at 150 GHz," Progress In Electromagnetics Research, Vol. 114, 177-194, 2011.

5. Dou, W.-B., H. F. Meng, B. Nie, Z.-X. Wang, and F. Yang, "Scanning antenna at THz band based on quasi-optical techniques," Progress In Electromagnetics Research, Vol. 108, 343-359, 2010.
doi:10.2528/PIER10062810

6. Kulesa, C., "Terahertz spectroscopy for astronomy: From comets to cosmology," IEEE Transactions on Terahertz Science and Technology, Vol. 1, No. 1, 232-240, 2011.
doi:10.1109/TTHZ.2011.2159648

7. Yeom, S., D. Lee, H. Lee, J. Son, and V. P. Gushin, "Distance estimation of concealed objects with stereoscopic passive millimeter-wave imaging," Progress In Electromagnetics Research, Vol. 115, 399-407, 2011.

8. Kemp, M., "Explosives detection by terahertz spectroscopy --- A bridge too far? ," IEEE Transactions on Terahertz Science and Technology, Vol. 1, No. 1, 282-292, 2011.
doi:10.1109/TTHZ.2011.2159647

9. Siegel, P. H., "Terahertz technology in biology and medicine," IEEE Transactions on Microwave Theory and Techniques, Vol. 52, No. 10, 2438-2447, 2004.
doi:10.1109/TMTT.2004.835916

10. Ajito, K. and Y. Ueno, "THz chemical imaging for biological applications," IEEE Transactions on Terahertz Science and Technology, Vol. 1, No. 1, 293-300, 2011.
doi:10.1109/TTHZ.2011.2159562

11. Cimini, D., R.Westwater, A. J. Gasiewski, M. Klein, V. Y. Leuski, and J. C. Liljegren, "Ground-based millimeter-and submillimeter-wave observations of low vapor and liquid water contents," IEEE Transactions on Geoscience and Remote Sensing, Vol. 45, No. 7, 2169-2180, 2007.
doi:10.1109/TGRS.2007.897450

12. Luini, L., C. Riva, C. Capsoni, and A. Martellucci, "Attenuation in nonrainy conditions at millimeter wavelengths: Assessment of a procedure ," IEEE Transactions on Geoscience and Remote , Vol. 45, No. 7, 2150-2157, 2007.
doi:10.1109/TGRS.2007.895336

13. Das, S., A. Maitra, and A. K. Shukla, "Rain attenuation modeling in the 10-100 GHz frequency using drop size distributions for different climatic zones in tropical India," Progress In Electromagnetics Research B, Vol. 25, 211-224, 2010.
doi:10.2528/PIERB10072707

14. Owolawi, P. A., "Rainfall rate probability density evaluation and mapping for the estimation of rain attenuation in south africa and surrounding islands," Progress In Electromagnetics Research, Vol. 112, 155-181, 2011.

15. Terasense, TeraSense: Project summary, 2012, http://www.ter-asense.org.

16. Liebe, H., G. Hufford, and M. Cotton, "Propagation modeling of moist air and suspended water/ice particles at frequencies below 1000 GHz ," AGARD, 52nd Specialists Meeting of the Electromagnetic Wave Propagation Panel, Vol. 1, 1993.

17. Rosenkranz, P., "Water vapor microwave continuum absorption: A comparison of measurements and models," Radio Science, Vol. 33, No. 4, 919-928, 1998.
doi:10.1029/98RS01182

18. Siles, G., J. Riera, and P. García-del-Pino, "Considerations on cloud attenuation at 100 and 300 GHz for propagation measurements within the TeraSense project," Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP), 2011.

19. Salonen, E. and S. Uppala, "New prediction method of cloud attenuation," Electronics Letters, Vol. 27, No. 12, 1106-1108, 1991.
doi:10.1049/el:19910687

20. Decker, M., E. Westwater, and F. Guiraud, "Experimental evaluation of ground-based microwave radiometric sensing of atmospheric temperature and water vapor profiles," Journal of Applied Meteorology, Vol. 17, No. 12, 1788-1795, 1978.
doi:10.1175/1520-0450(1978)017<1788:EEOGBM>2.0.CO;2

21. Mattioli, V., P. Basili, S. Bonafoni, P. Ciotti, and E. Westwater, "Analysis and improvements of cloud models for propagation studies," Radio Science, Vol. 44, No. 2, 2009.
doi:10.1029/2008RS003876

22. University of Wyoming, ``Upper air data: Soundings," 2012, http://weather.uwyo.edu/upperair/sounding.html.

23. Durre, I., R. Vose, and D. Wuertz, "Overview of the integrated global radiosonde archive," Journal of Climate, Vol. 19, No. 1, 53-68, 2006.
doi:10.1175/JCLI3594.1

24. Bosisio, A., E. Fionda, P. Basili, G. Carlesimo, and A. Martellucci, "Identification of rainy periods from ground based microwave radiometry ," European Journal of Remote Sensing, Vol. 45, 41-50, 2012.
doi:10.5721/EuJRS20124505

25. World Meteorological Organization, Manual on Codes --- International Codes, Part A, 2010.

26. Turner, D., A. Vogelmann, R. Austin, J. Barnard, K. Cady-Pereira, J. Chiu, S. Clough, C. Flynn, M. Khaiyer, J. Liljegren, et al. "Thin liquid water clouds," Bulletin of the American Meteorological Society, Vol. 88, No. 2, 177-190, 2007.
doi:10.1175/BAMS-88-2-177

27. Al-Ansari, K., P. García-del-Pino, J. Riera, and A. Benarroch, "One-year cloud attenuation results at 50 GHz," Electronics Letters, Vol. 39, No. 1, 136-137, 2003.
doi:10.1049/el:20030059

28. Siles, G., J. Riera, and P. García-del-Pino, "Estimation of total attenuation at 100 and 300 GHz using meteorological data in madrid," Proceedings of the ESA/ESTEC Workshop on Radiowave Propagation, 2011.

29. Radiosonde EU, , Stations de radiosondage en Espagne, (Radiosounding stations in Spain), 2012, http://www.radiosonde.eu/RS02/RS02K.html.

30. García-del-Pino, P., R. Rial, M. Cruz Moro, and A. Benarroch, "Experimental 0º isotherm height in Spain: Comparison with predictions and application for rain attenuation," Open Symposium n Propagation and Remote Sensing, URSI Comission-F, 2002.

31. ITU-R, , ITU-R recommendation P.676-8. attenuation by atmo-spheric gases, 2009.

32. ITU-R, , ITU-R recommendation P.840-5. attenuation due to clouds and fog, 2012.

33. Siles, G., J. Riera, and P. García-del-Pino, "On the use of radiometric measurements to estimate atmospheric attenuation at 100 and 300 GHz," Journal of Infrared, Millimeter and Terahertz Waves, Vol. 32, 528-540, 2011.
doi:10.1007/s10762-011-9770-0

Dr. Gustavo Adolfo Siles Soria

Dr. Jose M. Riera

Dr. Pedro Garcia del Pino

Dr. Jordi Romeu