A new study using NASA's Global Precipitation Measurement (GPM) mission data entitled "Water vapor and soil moisture can predict afternoon rainfall" was recently published in the Geophysical Research Letters journal. Many of us who use GLOBE protocols have wondered if we could use our data to help us answer some of the most challenging questions related to weather. This study might give some great ideas to students, teachers, and citizen scientists around the world to see if they can find similar results.
This article explains that the effect that water vapor has on weather is very complex and has not been well understood previously. The authors of this study look more closely at the possible relationship and came up with some rather surprising findings. One of the things that is so fascinating about science is that we can use emerging technologies and ground-based measurements to help us get a clearer understanding of what it taking place in Earth's systems.
For example, the lead author of this study, Josh Welty from the University of Arizona, states that the "prevailing wisdom on the relationship between soil moisture and rainfall is that if you have wetter soil in the morning, you’ll have a greater occurrence of rainfall in afternoon, but it’s more complicated than that.” One of the really interesting conclusions this study determined was that on days when the wind blows in only a little atmospheric moisture, we are more likely to get afternoon rains over wetter soils or where there is higher relative humidity. They found that when the wind blows in a lot of atmospheric moisture, you would be more likely to see rain over drier soils or in places with lower relative humidity.
The researchers state that this relationship between afternoon rainfall, atmospheric moisture, and soil moisture does not apply to the entire northern hemisphere. Wouldn't it be a neat study for GLOBE members all around the world to see what relationships they might find between soil moisture, water vapor, and afternoon rainfall? You could use both GLOBE protocol data as well as NASA satellite data to help you in this research.
If you are interested in seeing how much precipitation GPM measured over your location- or any location around the globe- check out this online interactive activity- "From Satellites to Your Backyard". You can also see how to compare and contrast your GLOBE precipitation data with that of GPM's data here. Finally, check out the last week of precipitation data which was observed around the world by the GPM mission here. How incredible that we have so much data to work with that is freely available, and we still have so many questions to ask and try to figure out! What are you waiting for- let's start investigating!