UTLS Transport

1
UTLS Transport STE Summary

• Finding Nemo
• Gettelman, Neu, Mullendore

2
Summary of Presentations (1)

• Haynes Dynamical theories for extratropical
  tropopause height
• No single definition is perfect. Trends matter!
  Tropopause climate
• Pan START 08 mixing in disturbed cases. Mixing
  happens not in the
• jet core but above and below jet.
• Tilmes Difference in mixing (Relative Altitude)
  between Sub-Tropics and Polar from in-situ data.
  Trace- tracer correlations.
• "regional differences more pronounced than
  seasonal differences
• Ray START08 Transport "Low Road" v. "High
  Road. Different time scales. Short transit times
  above tropopause up to Jet Top (intrusions)
• Vogel CLaMS Lagrangian model shows air mass
  origins for START08 RF1
• (intrusion) RF4 (fold). Coherent air mass
  origins! TTL air in LMS high lat
• Stone START08 WACCM nudged simulations of an
  intrusion
• Method for mapping intrusions in a global model

3
Summary of Presentations (2)

• Zhang GW during START08 Topographic waves
  dominate over Rockies
• Tarasick "Radar Tropopause" can pick out
  humidity gradients. Stratospheric intrusions
  common with rapid changes in trop height.
• Gille HIRDLS O3 Less mixing in winter, more in
  spring. PV O3 correlated. Above 350K Not much
  mixing or affect on O3.
• Santee MLS Vortex chemical processing of LMS
  air. Interannual variability large. O3 export to
  mid-lats (especially SH)
• Massie Smoke in Lower stratosphere (at
  tropopause). CALIPSO, MLS CO
• Rise does not appear due to convection. Are
  analyses good enough?
• May be due to absorptive heating of smoke.
• Konopka PDFs of O3/CO are good for comparison of
  Data and Models.
• Single mixing parameter (Kunz 2009). CLaMS
  agrees with START08

4
Summary of Presentations (3)

• Hoor CO H2O definitions of ExTL are Different
  different sources/sinks
• CO PV following. H2O preserves last saturation.
• James PreAVE and CR-AVE aircraft in Tropical
  Subtropical UTLS
• Air parcel origins. Tropical origin and synoptic
  perturbations mix.
• Miyazaki High vertical resolution GCM model
  results. TIL stronger at high resolution. TIL
  maintained by radiation and heat budget. 'Small
  scale' waves contribute to mixing
• Mizuta STE in a high horizontal resolution
  model. Gross STE smaller at
• high resolution. Net STE does not depend on
  resolution.
• Moustaoui TREX modeling studies of mountain
  waves.
• modulation of O3 CO depends on background
  tracer gradients
• Barth 4km Simulation of O3 over US. O3 due to
  Lightning NOx, convective precursor transport
  and STE (preliminary)

5
Discussion Points (1)

• Structure of Extratropical Tropopause Baroclinic
  eddies (Haynes)
• Modified by moist processes
• consistent theories, not fully unified
• Tropopause is a fingerprint of climate change
  (see later today)
• START08 Tracer-Correlations
• Mixing regions can see origin of mixing lines.
• source of air, transport pathways (CLaMS, Ray,
  James)
• Typical or not? (Gille O3 follows PV)
• TIL Structure Chemical aspects to it (Hoor)
• TIL maintenance Radiation Vertical Velocity
  (Miyazaki)
• Dynamical structure corresponds to tracer
  structure
• Profiler responds to H2O gradients (Tarasick
  intrusions, TIL)

6
Discussion Points (2)

• Tropopause folds and jet structures
• High Resolution Model, START08, WRF in N.
  American Monsoon
• Trop folds associate w. storm tracks (STE v.
  convection hard).
• Gravity Waves Perturb tracer fields, role in
  mixing.
• Importance of mid scales in high resolution
  models.

7
Discussion Integral View (Nemo!)

• PV and Static stability related
• So TIL is a mixing barrier
• ExTL is a result of this mixing barrier
  different depth for tracers with different
  sources
• Maintenance TIL PV Tropopause related
• TIL result of O3 and w-convergence
• Tropopause TIL Baroclinic eddies BD Circ
• ExTL/TIL breaks down where mixing occurs
• Folds, Intrusions, Fronts
• Small scale (GW, mixing) where events occur
• Important for STE