Tropical Cyclones

Overview

Tropical cyclones develop primarily in the summer months in regions with very warm sea surface temperatures, high low-level humidity and resulting instability that favors the development of thunderstorms, low amounts of vertical wind shear, and within the lower latitudes where these environments combine with a Coriolis force sufficient for establishing a surface area of lower pressure.  As they build in intensity, tropical waves and disturbances progress through categories of tropical depressions and named tropical storms, then to hurricanes and major hurricanes, the latter defined as a category three or higher on the Saffir-Simpson hurricane scale.  Tropical cyclones are readily observed in satellite imagery as organized clusters of thunderstorms in the lower tropical latitudes, and are much better known for the distinct, cloud-free eye common to major hurricanes as they move across the open oceans.  These cyclones bring large areas of damaging winds in addition to other threats from prolonged heavy rains and coastal inundation as a result of high storm surge, often requiring large evacuation zones when they threaten to impact populated areas, including the islands of the Pacific, southeastern Asia, and the Gulf Coast or eastern seaboard of the United States.

Tropical cyclones are frequently observed by NASA’s Global Precipitation Measurement (GPM) mission where their structure is made apparent through use of passive microwave brightness temperatures at various frequencies and polarizations.  In addition, their intense rainfall rates are readily mapped by the Integrated Multi-Satellite Retrievals for GPM (IMERG) product, and additional views of their three-dimensional structure made available through active radar scanning by the GPM core satellite.  Mapping of offshore heavy rain rates can provide responders with an expectation of what will occur after landfall, and improved identification of the storm’s center can aid tracking of the system and improved initialization with numerical weather prediction models.  Inland, rainfall estimates can be combined with streamflow and inundation models to understand flood risks resulting from the storm, and combined with topographical models and other information to characterize landslide threats.  Following landfall, flooding can be mapped using optical remote sensing from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the Terra and Aqua missions, the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the NASA/NOAA Suomi National Polar-orbiting Partnership (S-NPP) mission, or from the higher resolution views of the USGS/NASA Landsat-7 and Landsat-8 missions.  VIIRS also provides a unique opportunity to map power outages from space, which occur frequently as a result of landfalling tropical cyclones, and help to monitor the recovery of power in the days and weeks that follow.  Should post-storm cloudiness obscure a view of the land surface, synthetic aperture radar measurements of water extent from the European Space Agency’s Sentinel-1A and 1B platforms can assist with active scanning of inland surge and flood waters.  Finally, widespread damage to vegetation and treefall can be mapped over time from the aforementioned platforms, with ecosystem recovery monitored in the years that follow through consistent and continued imaging of the affected area

Latest Updates

October 2, 2017
ARIA Damage Proxy Map of Dominica from Hurricane Maria
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, created this Damage Proxy Map (DPM) depicting areas including Dominica that are likely damaged (shown by red and yellow pixels) as a result of Hurricane Maria (Category 5 at landfall in Dominica on Sept. 18, 2017). The map is derived from synthetic aperture radar (SAR) images from the Copernicus Sentinel-1 satellites, operated by the European Space Agency (ESA). The images were taken before (Mar. 27, 2017) and after (Sept. 23, 2017) the landfall of...
September 29, 2017
ARIA Damage Proxy Map for Puerto Rico
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, created this Damage Proxy Map (DPM) depicting areas of Western Puerto Rico that are likely damaged (shown by red and yellow pixels) as a result of Hurricane Maria (Category 4 at landfall in Puerto Rico on Sept. 20, 2017). The map is derived from synthetic aperture radar (SAR) images from the...
September 29, 2017
Map showing power outages in Puerto Rico
After Hurricane Maria tore across Puerto Rico, it quickly became clear that the destruction would pose daunting challenges for first responders. Most of the electric power grid and telecommunications network was knocked offline. Flooding, downed trees, and toppled power lines made many roads impassable. In circumstances like this, quickly knowing where the power is out—and how long it has been out—allows first responders to better deploy rescue and repair crews and to distribute life-saving supplies. And that...
September 26, 2017
NASA Damage Map Aids FEMA's Hurricane Maria Rescue Operation in Puerto Rico
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, created this Damage Proxy Map (DPM) depicting areas of Eastern Puerto Rico that are likely damaged (shown by red and yellow pixels) as a result of Hurricane Maria (a Category 4 hurricane at landfall in Puerto Rico on Sept. 20, 2017). The map is derived from synthetic aperture radar (SAR) images from the Copernicus Sentinel-1A and Sentinel-...
September 21, 2017
IMERG precipitation accumulation from Hurricane Maria 9/17/17 - 9/21/17
Hurricane Maria has caused catastrophic flooding in Puerto Rico. Extreme flooding was reported in the streets of San Juan, the capital of Puerto Rico. The National Weather Service issued flash flood warnings for the entire island. Hurricane Maria has now moved to the northwest of Puerto Rico but is still expected to contribute to rainfall over the island on Friday. Feeder bands are transporting rain over Puerto Rico and the Dominican Republic even as the hurricane moves toward the Turks and Caicos islands....

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