Temperature gradient

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A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature gradient is a dimensional quantity expressed in units of degrees (on a particular temperature scale) per unit length. The SI unit is kelvin per meter (K/m).

Temperature gradients in the atmosphere are important in the atmospheric sciences (meteorology, climatology and related fields).

Mathematical description[edit]

Assuming that the temperature T is an intensive quantity, i.e., a single-valued, continuous and differentiable function of three-dimensional space (often called a scalar field), i.e., that

T=T(x,y,z)

where x, y and z are the coordinates of the location of interest, then the temperature gradient is the vector quantity defined as


\nabla T = \begin{pmatrix}
{\frac{\partial T}{\partial x}},  
{\frac{\partial T}{\partial y}}, 
{\frac{\partial T}{\partial z}}
\end{pmatrix}

...

Weather and climate relevance[edit]

Differences in air temperature between different locations are critical in weather forecasting and climate. The absorption of solar light at or near the planetary surface increases the temperature gradient and may result in convection (a major process of cloud formation, often associated with precipitation). Similarly, on a global and annual basis, the dynamics of the atmosphere (and the oceans) can be understood as attempting to reduce the large difference of temperature between the poles and the equator by redistributing masses of warm and cold air (and water).

Meteorological fronts are regions where the horizontal temperature gradient may reach relatively high values, as these are boundaries between air masses with rather distinct properties.

Clearly, the temperature gradient may change substantially in time, as a result of diurnal or seasonal heating and cooling for instance. This most likely happens during an inversion. For instance, during the day the temperature at ground level may be cold while it's warmer up in the atmosphere. As the day shifts over to night the temperature might drop rapidly while at other places on the land stay warmer or cooler at the same elevation. This happens on the west coast USA sometimes due to geographical settings.

Day to day experiences and health issues[edit]

Other places where noticeable temperature gradients can be experienced include the entrance (or exits) of air conditioned shops in the summer, or the entrance of caves and other protected or poorly ventilated areas.

Rapid changes in temperature (in space or time) may cause discomfort and, in extreme cases, heat or cold stresses.

Indoor temperature[edit]

See also[edit]

References[edit]

  • Edward N. Lorenz (1967) The nature and theory of the general circulation of atmosphere, World Meteorological Organization, Publication No. 218, Geneva, Switzerland.[1]
  • M. I. Budyko (1978) Climate and Life, Academic Press, International Geophysics Series, Volume 18, ISBN 0-12-139450-6.[2]
  • Robert G. Fleagle and Joost A. Businger (1980) An Introduction to Atmospheric Physics, Second Edition, Academic Press, International Geophysics Series, Volume 25, ISBN 0-12-260355-9.[3]
  • David Miller (1981) Energy at the Surface of the Earth: An Introduction to the Energetics of Ecosystems, Academic Press, International Geophysics Series, Volume 29.[4]
  • John M. Wallace and Peter V. Hobbs (2006) Atmospheric Science: An Introductory Survey, Second Edition, Academic Press, International Geophysics Series, ISBN 0-12-732951-X.[5]
  1. ^ "The nature and theory of the general circulation of the atmosphere". by Amazon.com. 
  2. ^ "Climate and life". by Amazon.com. 
  3. ^ "An introduction to atmospheric physics". by Amazon.com. 
  4. ^ "Energy at the Surface of the Earth: An Introduction to the Energetics of Ecosystems". by Amazon.com. 
  5. ^ "Atmospheric Science, Second Edition: An Introductory Survey (International Geophysics)". by Amazon.com. 

External links[edit]