Vn-Vz

 

VOC

Abbreviation for Volatile Organic Compounds. These include various alkanes, alkenes, aromatics, aldehydes, and unspeciated compounds. See Jeffries (1995).

 

volcanic cooling

Explosive volcanic eruptions can inject enormous amounts of sulfur dioxide and ash into the atmosphere. These aerosol particles can result in climate changes lasting up to several years. Observed climatic responses to the Mt. Pinatubo eruption have included tropospheric cooling, stratospheric warming, and and overall drop of about 0.5 deg. C in the global average surface temperature.

 

vorticity

A fluid property that is defined as twice the local rate of rotation of a fluid element or the curl of the velocity field. It is a three-dimensional property of the field of motion of a fluid, although in large-scale geophysical fluid dynamics the vorticity component in the horizontal plane (i.e. rotation about the vertical axis) is usually the only non-negligible component. In a rotating frame of reference (such as on the Earth) we distinguish between the planetary vorticity, (2 U) i.e. the fluid partaking of the vorticity of the Earth at the given latitude, and the relative vorticity, ( u) i.e. the vertical component of the vorticity relative to the rotating frame, where U = x is the velocity of the rotating frame at position x.

 

vorticity equation

This is an equation used in large-scale geophysical fluid dynamics that relates the rate of change of the vertical component of vorticity to the horizontal divergence. It is derived by eliminating pressure (or geopotential) from the equations of motion. In cartesian co-ordinates it is

where is the vertical component of vorticity, f the Coriolis parameter, w the vertical velocity, the specific volume, and P the pressure. The first, or divergence, term on the right-hand-side dominates in large-scale motion. The second term represents the transformation of vorticity from the horizontal to the vertical component, and the third represents the direct generation of vorticity by horizontal density and pressure gradients.

 

vorticity vector

A measure of the rotational component of a velocity field. This is calculated by taking the curl of the velocity field, mathematically expressed by .

 

VTIR

Abbreviation for Visible and Thermal Infrared Radiometer.

 

VTPR

Abbreviation for Vertical Temperature Profiler Radiometer.