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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 19 (2011), Paper 26 Posted November 21, 2011 CORRELATED DISCRETE FREQUENCY EXCITATION OF RIO GRANDE DISCHARGE AND NEW MEXICO SNOWPACK DATA
J.L. Tichy ABSTRACT River discharge and montane snowpack play a central role in controlling processes at all levels of ecological organization, so the identification of dominant hydrological periods is an important issue in relating the physical system to the biological system. To quantitatively study the Rio Grande discharge along with the closely related snowpack, we determine the spectral densities as a function of frequency in addition to coherence estimates. This is quality-controlled through a signal to noise ratio, which also allows us to create a transfer function to model the relationship between river discharge and snowpack. By using frequency domain techniques, it becomes apparent that there are in fact three signal peaks at distinct frequencies (every 365 days, every 182 days, and every 122 days) for the riparian ecosystem of the Rio Grande in New Mexico, USA. By generalizing power spectral estimates, seasonal variation can be quantified (spring snowmelt in addition to summer monsoons) through spectrograms, yielding further amplitude estimates across a large band of frequencies of interest. Reference: Tichy, J.L. 2011. Correlated discrete frequency excitation of Rio Grande discharge and New Mexico snowpack data. Journal of Environmental Hydrology, Vol. 19, Paper 26. CONTACT: Jennifer L. Tichy University of New Mexico 10932 Jicama Way SE Albuquerque, NM 87123 E-mail: jltichy@gmail.com |
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