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Water Cycle Protocol Bundle

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Water, an essential component to life on Earth, continuously circulates through one of the planet's most powerful systems: the water cycle. Water flows endlessly between the ocean, atmosphere, and land, frequently changing forms as it moves between these domains.

Furthermore, the water on Earth is a finite, fixed quantity. This means that the amount of water in, on, and above our planet doesn't increase or decrease.

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Water Cycle Bundle

Studying the Water Cycle

NASA studies the water cycle with a variety of techniques. Researchers studying the water cycle use satellites, airborne campaigns, and ground-based measurements to collect data and learn more about how water circulates through our planet's various systems. This data is used in many real world applications to answer vital questions essential to our survival on this amazing “water planet.” The contributions from GLOBE scientists, teachers, and students are important elements supporting this effort, and directly help us become better stewards for the water in our environment.

Bundle Overview

  • Atmosphere
    • Surface Temperature
      • Surface temperature affects a local area's rate of evaporation. This rate determines how much water vapor is present in the atmosphere at any point in time.
    • Precipitation
      • The amount of precipitation that falls on an ecosystem influences how much water seeps into the soil and pools into reservoirs like lakes, rivers, and aquifers. 
    • Relative Humidity
      • Relative humidity is a measure of how much water vapor is present in the air and is a strong indicator of how rapidly water is moving from Earth’s surface, to the atmosphere, and back again
  • Pedosphere (Soil)
    • SMAP Soil Moisture
      • By studying soil moisture with satellite-assisted data like SMAP, we can draw conclusions on how the water cycle is functioning on a larger scale. Via soil moisture measurements, we can tell if an area is experiencing unusually wet or abnormally dry climatic conditions.
    • Soil Moisture (Gravimetric)​​​​​​
      • By taking soil moisture measurements from physical samples, we can not only verify satellite-gathered data, but we can also learn more about how moisture varies as we move further from the surface. These measurements are crucial for understanding how deeply the water penetrates the ground, how quickly water is evaporating, and how much water is likely to be gathered in natural reservoirs.

  • Hydrosphere
    • Water Temperature
      • The temperature of a water body influences its evaporation rate. This has direct consequences for the body's water level as well as the relative humidity and weather patterns for the surrounding habitat. 

Precipitation is a vital component of how water moves through Earth’s water cycle, connecting the ocean, land, and atmosphere. Knowing where and how much it rains, as well as the makeup of the precipitation, allows scientists to better understand how that precipitation affects rivers, surface runoff, and groundwater. When these measurements are conducted frequently with great detail, scientists can construct models of and determine changes to the Earth’s water cycle.

Scientific models of the water cycle help describe how water:

  1. Evaporates from the surface of Earth
  2. Rises into the atmosphere
  3. Cools and condenses into rain or snow in clouds
  4. Falls to the surface as precipitation

When this water falls back to Earth on land, it collects in rivers, lakes, soil, and porous rock layers, with much of it flowing back into the oceans. Throughout this drainage process, there are many chances for the water to reevaporate back into the atmosphere where it will begin the cycle once more. This cycling of water in and out of the atmosphere significantly influences many other aspects of life on Earth and is a direct driver of our regional weather patterns.


The water cycle is a key part of the Earth system that touches many different terrestrial, aerial, and marine domains. Furthermore, the fluxes and reservoirs that comprise it shift over time and space as a result of seasonal variation and climate change. Given the nature of these disparities and the influence the water cycle has on many aspects of the global environment, your data contributions are an important piece of the puzzle in characterizing how water moves through your local ecosystem. 



  • Claudia Caro
  • Olawale Oluwafemi (Femi)


  • Dr. Dixon Butler
  • Prof. Cartalis

Additional thanks to members of the GLOBE Science Working Group and Brian Campbell for improving the quality of the work.​​