Stratosphere-Troposphere Analyses of Regional Transport Experiment (START08) & Tropospheric Intrusion associated with the secondary tropopause from HIRDLS data Laura Pan With contributions from: Bill Hall, Paul Konopka, and HIRDLS team
Brief Overview of START08 • NCAR UTLS initiative - Integrated studies of coupled dynamics, chemistry, microphysics and radiation in the UTLS region (formed since 2003) • START - transport studies using tracers and tracer correlations • The concept of START was tested with limited payload during the test flight of HIAPER in Dec 2005 (START05).[Pan et al., 2007; Bowman et al., 2007; Young et al., 2007] • START08 (Pan, Elliot, Bowman) with Joint payload and flight operation with PreHIPPO project (Steve Wofsy), will be conducted April-May, and June 16-28, 2008 • 150 flight hours, Broomfield Colorado based • Collaborating satellite data and modeling activities
Primary Objectives of START08 • Investigate key transport processes that impact the chemical-microphysical distribution of the Ex-UTLS • Characterize the transport boundaries and transport pathways in the Ex-UTLS using tracer-tracer correlations Secondary Objectives Assist in the development and testing of the HIAPER aircraft payload and flight capabilities.
Scientific Issues • Transport Boundaries in the Ex-UTLS (i.e., the tropopause) • is the Is the extratropical tropopause better characterized as a surface or a layer? ExTL? • If a layer, how do we identify/define it? What controls its existence/depth? • STE and Transport pathways in the Ex-UTLS • How do we characterize or quantify STE? • Is flux the right number to go after? (not an observable) • What are the right observables to quantify? • The Behavior of the Secondary Tropopause • Role of Convective Transport • Role of gravity waves (GW) in the structure and composition of Ex-UTLS
START08 Strategy Right questions first, then right answers • Target key processes and identify key observables (dynamical variability, tracer correlations, age spectrum…) • Use physical evidence to identify the transport boundary • Relate dynamical variables to chemical compositions (for example, what is PV-ozone correlation in the tropopause region? How is it vary with space (lat/isentropes) and time (seasons) ? The role of other dynamical variables?)
START08 measurements II:GV Sampling Strategy Six flight scenarios in planning • Extratropical Tropopause and transition layer (ExTP/ExTL) Survey • Stratospheric intrusion (tropopause fold) • Tropospheric intrusion (poleward into lower stratosphere) • Convective transport • Gravity wave • Cirrus layer (single or multiple) near the tropopause
Satellite Data and Modeling Satellite data: • Participations NRT: HIRDLS (team),MLS (Olsen), AIRS/IASI (NOAA group), OMI (TBD), CALIPSO (TBD) Models involved: • WACCM (Doug Kinnison, Simone Tilmes, Andrew Gettelman) • CLaMs (Paul Konopka, Bill Hall) • Idealized GCM (Lorenzo Polvani) • Trajectory model (Kenneth Bowman) • WRF/MM5 (Fuqing Zhang and students) • Possible involvement of cloud resolving models (Ken Pickering and Pao Wang)
Scientific Questions III:The Behavior of the Secondary Tropopause • Does the secondary tropopause derived from the WMO definition have physical meaning? • Are there chemical transport processes associated with the secondary tropopause? • What are the microphysical behavior of the region of multiple tropopauses? • What dynamical processes control or contribute to the occurrence of the secondary tropopause?
Extensive/frequent occurrence of the multiple tropopause Randel et al., 2007
Influence of the secondary tropopause: Ozonesonde profiles BRATTS LAKE, CAN (50.2N,104.7W)
Microphysical implications of the secondary tropopause? Noel and Haeffelin, 2007
PV on θ = 335 K (day 8) Polvani, 2007 LC1: anticyclonic LC2: cyclonic
How do we quantify the chemical impact of the process? • Measurements of tracers of wide range of lifetimes in the layer is planned during START08 • Statistical analyses of HIRDLS ozone cross section is planned - contrast of zonal means of two types of cross sections • Trajectory and mixing modeling using CLAMS is in progress • Post START08 comparison and model analyses with WACCM (offline)
Thank You ! Shadows of Monument Valley - GV Flight 051209