Estimating Rainfall One Pixel at a Time: A Scientific Activity with Brazilian Students
Abstract
Studies of rainfall and precipitation using radars started almost at the same time as radars were developed for military applications in Second World War. Since then, the science behind radars used to monitor weather has evolved constantly. Radar images showing clouds, different types of precipitation, motion and evolution of weather systems are commonplace nowadays and are present in all forms of mass communication. Unfortunately, the layperson and even science students have limited knowledge of how weather radars work, how radar images are produced and what they do really mean. In order to increase the awareness about the use of radars in meteorology and interpretation of images, we started a program to teach science students on how to analyze radar images and to obtain simple estimates of rainfall using radar images alone. The data for the study was collected by a non-polarimetric Doppler radar operating on the C-Band The procedure is simple, radar images are selected, areas of interest (rain cells) are marked and then the color pixels in images are separated and counted according to their color and precipitation index. In this way, the evolution of the rain cell is followed and the amount of precipitation is calculated. As an additional activity, in a reverse analysis process, values of reflectivity are obtained from the estimates of precipitation and the size distribution of rain cloud droplets are calculated using parametric equations. This study was both rewarding and enriching for the students because they could participate in the actual process of collecting and analyzing the data, and the lessons learned and experience gained with this hands-on activity will certainly constitute a valuable asset.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMED53D0568A
- Keywords:
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- 0800 EDUCATION;
- 0845 EDUCATION / Instructional tools;
- 6952 RADIO SCIENCE / Radar atmospheric physics