Monday, 7 January 2013
Exhibit Hall 3 (Austin Convention Center)
Handout (147.6 kB)
Webcams are a common medium for the visual display of live weather conditions. News media, weather companies, and institutions use webcams to attract viewers, promoting instantaneous atmospheric field trips to their camera sites. Unfortunately, webcam systems offered by commercial venders can cost thousands of dollars, pricing much of this technology out of reach for many educational institutions with tight budgets. The Meteorology Program in the Department of Geography at Northern Illinois University has developed an economical network of webcams delivering live, high-definition, wide-angle perspectives of Midwestern skyscapes. Each constituent of the network cost less than $100; this includes a low-cost USB webcam offered by many online retailers or brick-and-mortar stores, a suction-cup mount, and USB extension cable. We employ free (i.e., donationware) and/or low-priced (i.e., $20) webcam software on second-hand, Windows-based computers to manage the network (e.g., capture images at set intervals, save images consecutively, FTP images, overlay text and timestamps). The webcams are placed on the interior side of windows that have partial or full sky views; the arrangement precludes the need for outdoor enclosures and maintains easy camera maneuverability. Beyond the initial benefit of allowing students to visually reach outside the classroom walls to see current weather, we have discovered that the real power of this resourceful webcam system is when we take the archived webcam images and compose time-lapse movies. Somewhat mundane, static images of clouds can be collected in a timeline and sped up 2X, 20X, or even 200X to reveal the dramatic fluid motion of the atmospheric "ocean". These cloudscape clips often inspire awe in students (and instructors!), promoting an awareness of the highly dynamical nature of the atmosphere. We have used time-lapse movies in introductory and upper-level atmospheric science courses to reveal features of meteorology inquiry, including: cloud classification, differential advection; outflow and lake-breeze boundaries; frontal passage; gravity waves and undular bore; thunderstorm development and maturation; shelf clouds associated with convective systems; levels of lifting condensation, free convection, and equilibrium; diurnal boundary layer; convective temperature; stratus undulations; etc. These elements are normally subtle or elusive in real-time, but come to life when the time-lapse technique is applied. We will discuss the requisite components and costs associated with the network, system bugs and solutions, open-source tools and automation (i.e., scripting) techniques for hands-off administration, construction of time-lapse movies using freeware, upload options to video-sharing websites, and instructional benefits of the system.
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