PMM

High in the atmosphere, water collects on dust and smoke particles in clouds. Raindrops start to form in a roughly spherical structure due to the surface tension of water. This surface tension is the "skin" of a body of water that makes the molecules stick together. The cause is the weak hydrogen bonds that occur between water molecules. On smaller raindrops, the surface tension is stronger than in larger drops. The reason is the flow of air around the drop. As the raindrop falls, it lose that rounded shape. The raindrop becomes more like the top half of a hamburger bun. Flattened on the...

Problem-Based Classroom Modules A series of PDF files which provide full classroom lessons and problem sets for a number of precipitation-related topics. The Shape of a Raindrop A lesson on what causes raindrops in our atmosphere to be a certain shape. Create a Sphere with Precipitation Climatology Click above to download the PDF file. This is an activity in which students will cut and fold paper to create a 3D sphere which displays the precipitation climatology (long-term average) computed by the Global Energy and Water Experiment for 1979-2008. This activity was created by Dr. Chris Kidd and...

Malaria outbreaks after the 2010 floods in Pakistan, E. coli and colliform from raw sewage in Mississippi flood waters, and cholera spread by heavy rains in Cameroon, West Africa are among the many health hazards associated with flood disasters and torrential rains. In developing regions with limited clean water infrastructure and health resources that are stretched thin, any advanced warning can make a huge difference in the health community’s response to help people in need. Flooding in Gonaives Haiti before and after the 2004 tropical storm Jeanne Using satellite data to forecast disease...

Soil moisture content is a measure of the amount of water in the soil. Knowing how much water is held in the soil is useful for many applications, including improving agricultural productivity, assessing drought and flood conditions, and even estimating groundwater supplies. NASA has teamed with the U.S. Department of Agriculture (USDA) - Foreign Agricultural Service (FAS) to develop a global soil moisture map fashioned for FAS by integrating soil moisture observations from the Earth Observing System Advanced Microwave Scanning Radiometer (AMSR-E) instrument into the USDA FAS soil moisture...

Visit the Land Data Assimilation Systems homepage Rain and snowfall are key components of land surface models, including the Land Data Assimilation Systems (LDAS), which integrate satellite and ground-based observational data to generate estimates of soil moisture, soil temperature, evapotranspiration and runoff. Scientists use this and other models to study surface features and how they change due to manmade and natural conditions such as urbanization and erosion. The Global LDAS (GLDAS) uses TRMM precipitation data in numerous investigations into how water and energy cycle through natural...