Chapter 3: isentropic analysis

3.1 isentropic coordinate system3.2 isentropic chart interpretation3.3 vertical motion on isentropic charts

isentropic coordinates

isentropic coordinates

isobaric coordinates

pros and cons of isentropic coordinates can be found in this meted module, by J. Moore

derivation of the equations of motion in isentropic coordinates: on blackboard

Isentropic maps: some examples infer vertical motion – low levels

900850800

L

285 K

295 K

450900

Isentropic maps: some examples same time, higher level

295 K – relative humidity suggests that storm-relative motion has an easterly component in E Montana

500

200

300

200

325 KIsentropic maps: some examples

same time, upper levels infer vertical motion – relate to QG argument

200

sample isentropic charts showing winds, pressure, and winds

• College of Dupage• OU

280 K

2014/03/28/12Z

310 K 290 K

2014/03/28/12Z

diagnosing vertical motion on isentropic charts:impact of storm motion

time 1 time 1 time 2c

(u,v)storm-relative = (u,v) - c

This is discussed further in Section 6 of this meted module, by J. Moore

vertical motion & diabatic processes

parcelperspective

layerperspective

textbook case study: 3 Jan 2002, 00 UTC296 K surface

500 mb height & abs vort - same time

500 mb height & SLPsame time

500 mb height & Q vectors & Q divergence - same time

500 mb height & 700 mb omega - same time

IDV 3D plot of 296K isentropic surfacewind vectors on this surface

same time (00 Z on 3 Jan 2002)

x Greensboro

Greensboro (GSO) soundingsame time

GSO

pressure and winds on the 296K isentropic surfacesame time

296K pressure & wind 296K pressure & storm-relative wind

c = 8.5 m/s towards the ESE

296K pressure & storm-relative wind & mixing ratio (g/kg) – same time

296K pressure & storm-relative wind & precipitation (dBZ) – same time