<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The infrared thermography has been successfully applied as a tool for high resolution imaging in different hydrological studies. This exploratory experimental study aimed at evaluating the possibility of using infrared thermography to determine the diameter of raindrops. Rain samples are collected on a pre-heated acrylic board, which is exposed to rain during an instant, and thermograms are recorded. The area of the thermal stains (“signatures” of the raindrops) emerging on the board is measured and converted to drop diameters, applying a calibration equation. Diameters of natural raindrops estimated using this technique were compared with laser disdrometer measurements; the Nash-Sutcliffe efficiency coefficient was used for evaluating the match between the resulting histograms of drop size distribution. Results confirm the usefulness of this simple technique for sizing and counting raindrops, although it is unsatisfactory in light rain or drizzle.</p></abstract>

The infrared thermography has been successfully applied as a tool for high resolution imaging in different hydrological studies. This exploratory experimental study aimed at evaluating the possibility of using infrared thermography to determine the diameter of raindrops. Rain samples are collected on a pre-heated acrylic board, which is exposed to rain during an instant, and thermograms are recorded. The area of the thermal stains (“signatures” of the raindrops) emerging on the board is measured and converted to drop diameters, applying a calibration equation. Diameters of natural raindrops estimated using this technique were compared with laser disdrometer measurements; the Nash-Sutcliffe efficiency coefficient was used for evaluating the match between the resulting histograms of drop size distribution. Results confirm the usefulness of this simple technique for sizing and counting raindrops, although it is unsatisfactory in light rain or drizzle.

Revisiting simple methods to estimate drop size distributions: a novel approach based on infrared thermography

Department of Civil Engineering, Faculty of Science and Technology of the University of Coimbra (FCTUC), Rua Luís Reis Santos, Campus II - University of Coimbra, 3030-788 Coimbra, Portugal

Institute of Marine Research (IMAR) and Marine and Environmental Sciences Centre (MARE), Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal

Rural Federal University of Pernambuco, Department of Agricultural Engineering, Rua Dom Manoel de Medeiros s/n, Dois Irmãos, CEP 50910-130 Recife, PE, Brazil

Journal of Hydrology and Hydromechanics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The infrared thermography has been successfully applied as a tool for high resolution imaging in different hydrological studies. This exploratory experimental...

Revisiting simple methods to estimate drop size distributions: a novel approach based on infrared thermography

Published Online: Jun 25, 2015

Page range: 220 - 227

Received: Nov 11, 2014

Accepted: Mar 02, 2015

DOI: https://doi.org/10.1515/johh-2015-0025

© 2015

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.