This dataset was developed as part of the EarthNow project, and shows the changes in the tropical zone boundaries over the last three decades.
The tropics are defined by the Easterly winds and are indicated in orange. They are the central belt of the world that is traditionally defined by a warm moist climate. In order to define the boundary of the tropics, satellites are used to measure the total column ozone differences between the tropics and the subtropics. This amount is then compared to past measurements and used to define the changing tropical boundary. In the past 30 years the boundary of the tropics has shifted on average 10 degrees latitude. The blue line is the tropical boundary of 1980-1984 while the red line in the boundary of 2008-2012. This expansion is significant, as it spreads the threat of tropical diseases as well as drought areas within the subtropics. This is even more important as this region of the world is home to most of the Earth's human inhabitants. Due to this shift, increased drought is forecasted for much of the world including southwestern United States, the Middle East, and southern Australia. These changes will also spread tropical diseases such as dengue fever and others, as there have been recent outbreaks in Florida, Portugal, and Russia. Understanding these changes in climate boundaries will offer great insight into the best ways to face these new conditions including vaccinations, food production, and urban development.
Through a collaboration with the Cooperative Institute for Meteorological Satellite Studies (CIMSS), the Cooperative Institute for Climate and Satellites (CICS-MD), and the NOAA Environmental Visualization Lab, EarthNow allows Science On a Sphere (SOS) institutions to go beyond the scientific facts to create meaningful visitor experiences about weather and climate connections. The EarthNow Team regularly updates the website, providing a central location for SOS facilitators to find timely weather and climate stories to speak about how current events affect and are affected by global change. Along with these stories, the website also provides relevant, visually appealing SOS-formatted datasets and animations with appropriate annotations, leading to easier comprehension by presenters and the public.
You can visit the blog here and download datasets from past blog entries here!