GPM

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...

TRMM overpass of Hurricane Arthur from July 3, 2014. View fullscreen in STORM Event Viewer 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...

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 dynamics of a regional...