Tropical Cyclones on MW OI SST: GlobalTropical Cyclones on MW OI SST: GlobalTropical Cyclones on MW OI SST: GlobalHurricanesHurricanesHurricanesWhat makes a hurricane? ¾ First, warm water - at least 82 degrees, in fact. ¾ Several weeks after the Sun shines brightest on the tropics in late June in the northern hemisphere, the waters reach their warmest. ¾ Here, orange and red indicate the necessary 82-degree and warmer water, sea surface temperatures (SSTs) taken by the Advanced Microwave Scanning Radiometer-EOS (AMSR/E) aboard the Aqua satellite from beginning in June 2002. ¾ Next, add a disturbance, generally easterly waves off of Africa, formed from winds resulting from the clash between the hot Sahara Desert and the cooler Gulf of Guinea. ¾ These waves provide the initial energy and spin required for a hurricane to develop, as imaged by the Geostationary Operational Environmental Satellite (GOES, operated by NOAA) on Sept. 1-15, 2001. Credit: NASA¾ With the right mix of winds and SSTs, an ordinary cluster of tropical thunderstorms can explode into a tropical storm. Winds converge, forming the familiar circular pattern of clouds. Warm, rising air in the storms draws water vapor up from the ocean. The vapor condenses in clouds and releases heat, warming the eye, evaporating more surface water and feeding the hurricane's heat engine, continuing the cycle.Data from Hurricane Erin, Sept. 10 - 15, 2001.a) wind speed/direction, from Seawinds instrument on QuikScat satellite [NASA]b) cloud structure, from Visible and Infrared Scanner (VIRS) on the Tropical Rainfall Measuring Mission (TRMM) satellite [NASA/NASDA]c) rainfall rates (green, in excess of 2 inches per hour), Microwave Imager (TMI) and Precipitation Radar (PR) on TRMM [NASA/NASDA]d) eye warmth (red), Convection And Moisture EXperiment(CAMEX) [NASA]e) GOES [NASA/NOAA]HurricanesHurricanesHurricanes¾ Hurricanes essentially act as engines, drawing energy up from warm tropical ocean waters to power the intense winds, powerful thunderstorms, and immense ocean surges. ¾ Water vapor from the warm ocean surface evaporates, forming towering convective clouds that surround the eyewall and rainbandregions of the storm. ¾ As the water vapor cools and condenses from a gas back to a liquid state it releases latent heat. ¾ The released heat warms the surrounding air, making it lighter and promoting more clouds.¾ Because the hurricane-speed winds surrounding the clear eye are often absent from the center of a hurricane, the heaviest rain clouds are pushed out to form a ring around the center, leaving a relatively fair-weather eye.HurricanesHurricanesHurricanesHurricanesHurricanesHurricanesAMSR data showing mostly cool waters off the African coast (3/3/2003)AMSR data showing mostly cool waters off the African coast (7/3/2003)HurricanesHurricanesHurricanesGOES data showing disturbances of the coast of Africa coast (9/6/2001)GOES data showing more disturbances of the coast of Africa coast (9/6/2001)HurricanesHurricane Erin: MODIS VIRS – IR and TRMM rainfall (9/10/2001)HurricanesHurricanesHurricane Erin: MODIS VIRS Hurricane Erin: MODIS VIRS ––IR and TRMM rainfall IR and TRMM rainfall (9/10/2001)(9/10/2001)HurricanesHurricane Erin: MODIS VIRS – IR and TRMM rainfall (9/10/2001)HurricanesHurricanesHurricane Erin: MODIS VIRS Hurricane Erin: MODIS VIRS ––IR and TRMM rainfall IR and TRMM rainfall (9/10/2001)(9/10/2001)HurricanesHurricane Erin: MODIS VIRS – IR and TRMM rainfall & warmth (9/10/2001)HurricanesHurricanesHurricane Erin: MODIS VIRS Hurricane Erin: MODIS VIRS ––IR and TRMM rainfall & warmth IR and TRMM rainfall & warmth (9/10/2001)(9/10/2001)HurricanesHurricane Erin: MODIS VIRS – IR and GOES-IR(9/10/2001)HurricanesHurricanesHurricane Erin: MODIS VIRS Hurricane Erin: MODIS VIRS ––IR and GOESIR and GOES--IRIR(9/10/2001)(9/10/2001)HurricanesHurricane Erin: MODIS bluemarble and GOES-IR(9/10/2001)HurricanesHurricanesHurricane Erin: MODIS Hurricane Erin: MODIS bluemarblebluemarbleand GOESand
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