Articles

In addition to the powerful winds that have raked the northern Bahamas over the past few days, Hurricane Dorian’s slow motion has 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 check...

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 estimates come...

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. The movie shows NASA's IMERG precipitation estimates for May 1 through July...

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 warm buoyant air to rise...