Collaborative UT/LS Research Interests at NCAR and the Use of HIAPER

1. Collaborative UT/LS Research Interests at NCAR and the Use of HIAPER ACD: L. Pan, S. Schauffler, W. Randel, B. Ridley MMM: M. Barth (also ACD), D. Lenschow (also ATD), A. Heymsfield ATD: J. Stith, D. Rogers, T. Campos CGD: P. Rasch

2. Motivations • Important impact - Ozone, water vapor, cirrus clouds, and aerosols have major effects on Earth’s radiation budget • Complicated processes - Multiscale transport and exchange between LS and UT, strong gradients in trace constituents, and multiphase chemistry • Common interest - critical mass of collaborators interested in chemistry,dynamics and microphysics of UT/LS • New tools - the AURA satellite (2004) and HIAPER (2005)

3. Dynamics, Chemistry, and Clouds in UT/LS

4. Inter-related scientific issues in UT/LS transport - chemistry - clouds • Seasonal variations in ozone and water vapor are controlled by transport and chemistry; • Production and loss of ozone in this region is very sensitive to radicals (HOx,NOx, ROx ClOx, BrOx) and their precursors, which can be brought to UT by convective transport; • Cloud processing/tranport of chemical species and production of NOy by lightening link convection to upper tropospheric chemistry;

5. Scientific Issues (cont.) • Multiphase chemistry associated with aerosols and cloud particles is not well understood; • Aerosol composition in the upper troposphere depend on transport history

6. Integrated studies using satellite data, HIAPER, and models • Satellite observations provide spatial temporal coverage needed for global modeling efforts; • Aircraft provide observations of small-scale processes in targeted areas; • New models can provide powerful tools for designing observational studies and interpreting the measurements.

7. Tropopause in the Extratropics Thermal tropopause derived from the Microwave Temperature Profiler (MTP/JPL, Gary/Mhoney) data (TOTE/VOTE) and PV, zonal wind fields from UKMO analyses

8. DIAL ozone (Browell) , MTP tropopause (Gary/Mahoney), UKMO PV

9. DIAL ozone (Browell) , MTP tropopause (Gary/Mahoney), UKMO zonal wind

10. Model (CLaMS) Investigation of SONEX flight 10 L. Pan et al., work in progress

11. A Mixing Layer Revealed by Tracer Correlation • ER-2 measurements across the extratropical tropopause in two latitudinal locations; • Colors indicate the data points are above (red) or below(green) the thermal tropopause; • The characteristics of the mixing layers are different at the two latitudinal locations, showing the influence of the subtropical jet. L. Pan work in progress

12. Figure 1, Schematic of the convective injection of peroxides and the cycling of HOy in the upper troposphere [Cohan et al., 1999].

13. Net ozone production (24 hour average) as a function of NOx above 8 km. Blue pluses are steady state point model calculations and red solid circles are steady state observed calculations. The three curves show model calculations for average conditions during SUCCESS at 11 km, assuming different levels of HOx source. The dashed line assumes the peroxides and formaldehyde to be at steady state, the dotted line uses the same steady state assumption but does not include production of HOx from acetone photolysis, and the solid line assumes a convective source of peroxides and formaldehyde with acetone photolysis [Jaegle et al., 1998].

14. SUBVISUAL CIRRUS Heymsfield(1986)

15. Monsoon circulation and STE (Dethof et al. 1999) Randel et al., JGR 2001

16. Satellite Platforms - AURA/HIRDLS • The AURA satellite is scheduled to be launched in 2004 for a nominal mission of five years. Four instruments on board are: HIRDLS, MLS, OMI, and TES. • HIRDLS (NCAR/ACD involved) observes global distribution of temperature and concentrations of O3, H2O, CH4, N2O, NO2, HNO3, N2O5, CFC-11, CFC-12, ClONO2, and aerosols in the upper troposphere, stratosphere, and mesosphere. • High resolution measurements (vertical ~1 km and horizontal ~ 4x5 Lat-Lon). • HIAPER campaigns in UT/LS regions, in addition to the defined scientific objectives, may also contribute to AURA/HIRDLS validation.

17. HIAPER - an ideal platform for UT/LS studies • High altitude capability that is ideal for mid latitude UT/LS studies • Long flight duration for broad spatial coverage in the tropopause region • Capacity for reasonable sized chemistry/tracer/aersol/radiation instrument complement • Possibility of having significant remote sensing capability onboard

18. HIAPER measurements that can contribute to the UT/LS studies • Meteorological parameters: temperature and temperature profiles, pressure, winds, … • In situ and Remote sensing measurement of chemical tracers: O3, H2O (total water and isotopes) , CO, CH4, N2O, CO2, halocarbons • Ozone photochemistry: NOy, species contributing to NOy, HOx, RO2, CH2O, peroxides, hydrocarbons, photolysis rates, …

19. HIAPER measurements (cont.) • Cloud and aerosols: Aerosol and hydrometeor size distributions, condensed water content, extinction coefficient, asymmetry parameter, CCN, aerosol compositions • Sampling rates for small-scale processes - 25 per second; for mean structure-2 per second • onboard calculation and display of variables to facilitate flight planning

20. Collaborative UT/LS Research at NCAR • To identify key scientific issues in UT/LS research and to define our primary objectives (in progress); • To design an infrastructure to implement a collaborative effort; • To plan HIAPER campaigns for the defined UT/LS scientific objectives in conjunction with university and other collaborators.