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

September 27, 2016
GPM Precipitation data from Typhoon Megi
Three typhoons have battered Taiwan in the past few weeks. Super Typhoon Meranti, the strongest typhoon of the year, caused havoc as it passed to the south of Taiwan on September 14, 2016. Typhoon Malakas clipped northeastern Taiwan a few days later. Typhoon Megi has now caused injuries, deaths and destruction as it passes over northeastern Taiwan. The GPM core observatory satellite passed over on September 26, 2016 at 2231 UTC when typhoon Megi was approaching...
October 23, 2015
Tropical Cyclone Intensification (TCI) HIRAD Instrument
Report from Dan Cecil/HIRAD PI: Takeoff today was at 1808 UTC, the WB-57 should get over the storm around 20 UTC (3 CDT).   Data collection has gone smoothly so far, and initial processing of data from the first flight (Wednesday) was also nominal.   Data from the second flight was just downloaded this morning, during preparations for today’s flight. Landfall expected tonight, therefore WB-57 will not fly 24 Oct as TCI is an over water mission
October 23, 2015
Hurricane Patricia as seen from the International Space Station on Friday afternoon, October 23, 2015
The ISS sees Hurricane Patricia.  Hurricane Patricia as seen from the International Space Station on Friday afternoon, October 23, 2015   Wind speed and direction near the ocean surface, as measured on October 23 by the ISS-RapidScat. Brighter shades of blue represent stronger surface winds.

Pages