Featured Articles Archive

  • Hurricane Dorian Brings Heavy Rain to Bahamas
    In addition to the powerful winds that have raked the northern Bahamas over the past few days, Hurricane Dorian’s slow motion has also brought very heavy rainfall to the islands as well. Dorian first formed into a tropical depression on the 24th of August about 800 miles east southeast of Barbados in the Lesser Antilles from an area of low pressure; the depression was quickly upgraded to a minimal tropical storm and named Dorian by the National Hurricane Center (NHC) later in the day. As Dorian made its way westward under the influence of a high pressure ridge to the north, it was held in...
  • IMERG Measures Rainfall in Hurricane Dorian
    UPDATE 9/9/19: On Monday morning, September 9, Hurricane Dorian was a post-tropical storm after a mid-latitude weather front and cold seas had altered its tropical characteristics over the weekend. On Saturday and Sunday, Hurricane Dorian struck eastern Canada, causing wind damage and bringing heavy rainfall.  According to the Associated Press, a peak of 400,000 people were without power in Nova Scotia, Canada, because of Dorian. This graphic shows precipitation that fell during the almost two-week period from August 27 to the early hours of September 9. The near-realtime rain...
  • Rain Patterns During the Alaska Wildfires
    NASA's satellite-based estimate of global precipitation can provide valuable information to officials monitoring the many wildfires in Alaska this summer.  Wildfires occur in Alaska each summer, but July 2019 is shaping up to be a particularly active month.  Few rain gauges exist in the large tracts of Alaskan wilderness, but wildfires unchecked can spread to populated areas within the state.  Satellite-based precipitation estimates are particularly valuable here because of precipitation's relationship to wildfire hazard.
  • Observing the Intertropical Convergence Zone with IMERG
    The intertropical convergence zone or “ITCZ” roughly forms a band that circumnavigates the Earth near the Equator where the northeast trade winds in the Northern Hemisphere converge with the southeast trade winds in the Southern Hemisphere.  Sailors have often referred to it as the “doldrums” due to its generally light winds.  Yet, the ITCZ is an important part of the global circulation as it forms the ascending branch of the Hadley circulation.  This is ultimately driven by incoming solar radiation, which peaks near the Equator.  This warms the air and the ocean, causing...
  • 5 Year Anniversary of Hurricane Arthur
    June marks the official start of the Atlantic hurricane season. And although strong tropical cyclones are rare in June in the Atlantic, it will soon be the 5-year anniversary of Hurricane Arthur, which became a tropical depression in very late June 2014 before hitting the Outer Banks of North Carolina as a Category 2 hurricane in early July. As with most storms early in the season, Arthur formed not from a tropical wave moving off the coast of Africa but from an old frontal boundary that stalls off the coast and provides a focus for shower and thunderstorm activity over warm water. With...
  • How TRMM and GPM Study Latent Heating
    Latent heating (LH) arises predominantly from the release of heat associated with the condensation of water vapor into cloud droplets in clouds with active updrafts.  Other sources of LH include ice deposition and freezing, while evaporation, melting and sublimation induce cooling, but condensation is the dominant heating term.  Like a hot-air balloon, LH can keep air parcels warmer than their surrounding environment and therefore rising.  On a large scale, LH is responsible for driving the ascending branch of the Hadley Circulation.  LH is also an important component in...
  • The 2019 Atlantic "hurricane season" is officially upon us and runs through November 30th. Did you know that GPM data play a fundamental role in the ability to monitor existing storm activity such as capturing the location and intensity of rainfall inside a storm, as well as improving weather and precipitation forecasts through assimilation of instantaneous precipitation information? Here are a few applications of GPM data used to study hurricanes and how the data was then used for decision-making.
  • Finding Strong Storms with TRMM & GPM
    Spring is severe storms season here in the US, but not everyone has NEXRAD radar coverage; however, NASA’s TRMM and GPM satellites with their onboard radars have made it possible to search the entire global Tropics and midlatitudes and systematically identify areas where there are strong to intense thunderstorms. Researchers now headed by Dr. Chuntao Liu at Texas A&M University have built a comprehensive database of “precipitation features” based on regions of contiguous radar echoes from first the TRMM and now the GPM satellite. These precipitation features can then be mined to locate...

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