Glossary and Acronyms: H

h 1/3:

significant wave height/swell hight. Average height of the highest one-third waves, close to the height naturally estimated with eyes.

h max:

maximum wave/swell height. Often close of twice the significant wave height/swell height.

Hadley cell:

a direct thermally driven and zonally symmetric circulation under the strong influence of the earth's rotation, first proposed by George Hadley in 1735 as an explanation for the trade winds. It consists of the equatorward movement of the trade winds between about latitude 30° and the equator in each hemisphere, with rising wind components near the equator, poleward flow aloft, and, finally, descending components at about latitude 30° again.

HIRS :

High Resolution Infrared Radiation Sounder. HIRS, flown on NOAA-15 to 19, is an atmospheric sounding instrument that provides provide high resolution temperature soundings of the global atmosphere in cloud-free conditions of great importance to meteorology and climatology.

Hydrostatique approximation:

assumption that the hydrostatic equation aplies, i.e. that vertical accelerations are negligible.
A hydrostatic model is an atmospheric model for which the hydrosatatic assumption si made.
The hydrostatic pressure is the downward force exerted on a surface due to the gravitational attraction acting on the overlying fluid.

Hurricane:

Used in the Western Hemisphere (North Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern and central North Pacific east of the date line) to designate the same phenomenon than the tropical cyclone on the South-West Indian Ocean (tropical system whose winds reach Beaufort scale force 12 (above 63 knots/118km/h).
The name is derived from "huracan", a Taino and Carib god, or "hunraken", the Mayan storm god.

Hurricane warning:

meteorological message intended to warn those concerned of the dangerous effects of a hurricane with a wind of Beaufort scale force wind 12 or greater over a specific area.

hPa:

a hectoPascal is equal to 100 Pascals or 1 millibar.

HRPT :

High Resolution Pictures Transmission.