Cooling Solutions for Phoenix's Heat Islands

Phoenix, Arizona is one of the fastest growing cities in the United States. It is also the hottest, and as more and more of the landscape is developed, the land loses its natural capability to cool itself, thereby creating an increasing public health issue. Climate scientists at ASU, land developers, public officials, and citizens in the hottest parts of Phoenix are attempting to cool things down a little. They used NASA ASTER and LANDSAT satellite imagery, paired with census information and heat-related public health data, to assess which neighborhoods are the hottest and in direst need of help. ASTER imagery was used to analyze heat surface temperatures, and LANDSAT was analyzed using NDVI to look at the overall vegetation cover and the greenness. This study found three neighborhoods to target with new heat-reduction development and revitalization practices, including tree and shrub planting, installing shading structures at rest areas and parks, and repaving streets and sidewalks with heat-reflecting materials.

 https://www.washingtonpost.com/graphics/2020/climate-solutions/phoenix-climate-change-heat/

Using Thermal Satellite Data to Predict Famines

  

Image 1: The first thermal images received from ASTER sensor on the Terra satellite of Ethiopia, 15 years ago.  Thermal images like this are what Senay uses to monitor crop health in Ethiopia.  

  

Gabriel Senay is a Research Physical Scientist with the US Geological Survey.  He has developed a way to use thermal data from NASA's Terra and Aqua satellites, which record Earth's temperature for every square kilometer daily, along with historical temperature data from NOAA and the University of California at Berkeley.  

In the past scientists have used a land's greenness to monitor the health of vegetation in an area.  The problem with using greenness is that vegetation can stay green for weeks even after the crops have become stressed and begun dying.  

 

 Image 2: Map by Guilbert Gates; Source: Eros  

  

Senay's technique uses thermal imaging to look at how plants "sweat" - evapotranspiration - to see how healthy they are.  Evapotranspiration is a cooling process.  When plants aren't releasing as much moisture, such as in the beginning of a drought, the land become hotter.  These changes in temperatures can be seen almost immediately.  Senay has found that these spikes in temperature are a reliable quick way to judge if an area is about to experiance a drought.  Senay is focusing specifically on Ethiopia where there are rural farms and ranches which do not often have easy ways to communicate with agencies that could help during a drought.  Senay hopes to take this monitoring a step further and create a mobile app where farmers can report their land changes as well as see weather forecasts.  This app would also help connect experts, monitoring thermal data, to more quickly send aid to farmers before a drought, and famine, is in full swing.  

  

Sources:  

https://globalmonitoring.sdstate.edu/content/senay-gabriel  

http://www.smithsonianmag.com/innovation/predict-famine-before-strikes-180954945/?no-ist  

http://terra.nasa.gov/areas/aster 

  

by Tess MacFarlane