A two-dimensional plot showing how the value of some quantity varies in space-time; one axis refers to time and the other to spatial location. It is particularly used in meteorology.
Hovmöller diagram. The diagram shows the recorded rain intensity along a 30km path during a 24-hour period.
- Harold I (850–933)
- Harold II (1020–66)
- HARP
- Harper, Stephen (1959–)
- harpoon mechanism
- harp tank
- harrier
- Harris, Bernard Jr (1956– )
- Harrison, Benjamin (1833–1901)
- Harrison, John
- Harrison, Ross Granville
- Harrison, William Henry (1773–1841)
- Harrod-neutral technical progress
- Harrod–Domar growth model
- Harrop formula
- Harsha (590–647)
- hartebeest
- Hartebeesthoek Radio Astronomy Observatory
- Hartford Convention (1814–15)
- Hart, Herbert Lionel Adolphus (1907–92)
- Hartley, David (1705–57)
- Hartley, Herman Otto (1912–80)
- Hartley oscillator
- Hartley test
- Hartline, Haldan Keffer