Convective inhibition
Convective inhibition (CIN or CINH)
CIN is the amount of energy required to overcome the negatively buoyant energy the environment exerts on an air parcel. In most cases, when CIN exists, it covers a layer from the ground to the level of free convection (LFC). The negatively buoyant energy exerted on an air parcel is a result of the air parcel being cooler (denser) than the air which surrounds it, which causes the air parcel to accelerate downward. The layer of air dominated by CIN is warmer and more stable than the layers above or below it.
The situation in which convective inhibition is measured is when layers of warmer air are above a particular region of air. The effect of having warm air above a cooler air parcel is to prevent the cooler air parcel from rising into the atmosphere. This creates a stable region of air. Convective inhibition indicates the amount of energy that will be required to force the cooler packet of air to rise. This energy comes from fronts, heating, moistening, or mesoscale convergence boundaries such as outflow and sea breeze boundaries, or orographic lift.
Typically, an area with a high convection inhibition number is considered stable and has very little likelihood of developing a thunderstorm. Conceptually, it is the opposite of CAPE.
CIN hinders updrafts necessary to produce convective weather, such as thunderstorms. Although, when large amounts of CIN are reduced by heating and moistening during a convective storm, the storm will be more severe than in the case when no CIN was present.[citation needed]
CIN is strengthened by low altitude dry air
CIN is calculated by measurements recorded electronically by a
The CIN energy value is an important figure on a skew-T log-P diagram and is a helpful value in evaluating the severity of a convective event. On a skew-T log-P diagram, CIN is any area between the warmer environment virtual temperature profile and the cooler parcel virtual temperature profile.
CIN is effectively negative buoyancy, expressed B-; the opposite of convective available potential energy (CAPE), which is expressed as B+ or simply B. As with CAPE, CIN is usually expressed in J/kg but may also be expressed as m2/s2, as the values are equivalent. In fact, CIN is sometimes referred to as negative buoyant energy (NBE).
See also
References
- "National Weather Service Glossary - C". 21 April 2005. Retrieved August 22, 2006.
- Haby, Jeff (February 28, 2004). "Ingredients for Thunderstorms and Severe Thunderstorms". The Weather Prediction.Com. Retrieved August 22, 2006.
- Bol, Alan (2002). "Buoyancy and CAPE". Principles of Convection I. University Corporation for Atmospheric Research. Retrieved August 22, 2006.
- "Skew-T Mastery". University Corporation for Atmospheric Research. Retrieved April 24, 2007.
- David O. Blanchard (September 1998). "Assessing the Vertical Distribution of Convective Available Potential Energy". Weather and Forecasting. 13 (3): 870–877. S2CID 124375544.