5: Atmospheric Stability
- Page ID
- 9560
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)A sounding is the vertical profile of temperature and other variables in the atmosphere over one geographic location. Stability refers to the ability of the atmosphere to be turbulent, which you can determine from soundings of temperature, humidity, and wind. Turbulence and stability vary with time and place because of the corresponding variation of the soundings.
We notice the effects of stability by the wind gustiness, dispersion of smoke, refraction of light and sound, strength of thermal updrafts, size of clouds, and intensity of thunderstorms.
Thermodynamic diagrams have been devised to help us plot soundings and determine stability. As you gain experience with these diagrams, you will find that they become easier to use, and faster than solving the thermodynamic equations. In this chapter, we first discuss the different types of thermodynamic diagrams, and then use them to determine stability and turbulence.
- 5.0: Homework Exercises
- This page of the textbook covers atmospheric thermodynamics, focusing on practical applications through online resources and exercises involving rawinsonde data, thermodynamic diagrams, and atmospheric stability. It discusses key variables like temperature, dew point, and pressure, alongside exercises for analyzing air parcels and static stability.
- 5.1: Large-Size Thermo Diagrams
- This page provides permission and guidelines for using seven thermo diagrams for personal and educational use, detailing the line types for atmospheric parameters like temperature and pressure. It describes the labels and units for isobars, isohumes, height, and adiabatic lines. Two versions of the Skew-T and θ-Z diagrams for various studies are included, with a recommendation for clean copies to ensure accuracy in reproductions.
- 5.2: Building a Thermo-Diagram
- This page covers the components and uses of thermodynamic diagrams, particularly the Emagram, which combines isopleths like isobars, isotherms, and adiabats for atmospheric data analysis. It differentiates between adiabatic and pseudoadiabatic processes affecting air parcel temperature. The evolution and optimization of these diagrams in meteorology are discussed, along with their various types tailored for specific meteorological applications.
- 5.3: 5.2. Types of Thermo Diagrams
- This page provides an overview of thermodynamic diagrams in meteorology, including the Emagram, Stüve and Pseudoadiabatic diagrams, Skew-T Log-P diagram, Tephigram, and Theta-Height diagrams. It explains how these diagrams plot temperature against pressure, depicting features like dry and moist adiabats, isotherms, and isobars. The page emphasizes the graphical traits and applications of each diagram in representing atmospheric thermodynamic properties and processes.
- 5.4: More on the Skew-T
- This page covers the creation and interpretation of Skew-T diagrams, comparing them to Emagrams and focusing on their unique curved isobars. It outlines a step-by-step method for creating a Skew-T using a graphics program, highlights the significance of the skewness factor, K, and provides equations for plotting isotherms and adiabats.
- 5.5: Guide for Quick Identification of Thermo Diagrams
- This page presents a method for identifying various types of thermo diagrams, including Skew-T, Tephigram, θ-Z, Emagram, and Stüve. It details key features to recognize, such as isobars, dry and moist adiabats, isotherms, and isohumes, highlighting that isobars appear as straight horizontal lines and moist adiabats are highly curved.
- 5.6: Thermo-Diagram Applications
- This page covers the representation of air parcels on a Skew-T diagram, focusing on key points like temperature and dew-point in relation to lifting condensation level (LCL). It addresses the dynamics of cloud formation, saturation, and the effects of radiative heating and cooling on clouds, emphasizing the roles of both diabatic and adiabatic processes.
- 5.7: An Air Parcel and its Environment
- This page covers air column dynamics, defining "sounding" as a vertical environmental profile and explaining the lapse rate, temperature, dew point data, and buoyancy forces on air parcels. It introduces the Brunt-Väisälä frequency, essential for analyzing stability and oscillation of air parcels, and provides equations for calculating these parameters.
- 5.8: Flow Stability
- This page examines atmospheric stability, focusing on its response to disturbances and categorizing it into stable, unstable, or neutral states. It describes five stability types based on lapse rates and emphasizes conditional stability's role in thunderstorms. The interaction of buoyancy and wind shear is analyzed through static and dynamic stability, using the bulk Richardson number (Ri).
- 5.9: Finding tropopause Height and Mixed-Layer Depth
- This page covers the tropopause and mixed-layer in the atmosphere. The tropopause serves as a barrier to vertical weather movement and varies with latitude and season. The mixed-layer, created by surface heating, facilitates air mixing but is capped by stable layers that can trap pollutants, making its depth important for air quality. Techniques for identifying these layers from soundings are also discussed.
- 5.10: Review
- This page discusses the importance of thermo diagrams, such as Emagrams and Skew-T diagrams, which are vital for estimating the thermodynamic state of air concerning pressure, temperature, and moisture. They provide insights into air changes from processes like heating and cooling, assist in estimating cloud heights, and analyze air parcel behavior.