1. How Has It Been Conducted? How Has It Been Conducted? Campaign Basis Campaign Basis International collaboration (NOAA, INAMHI, LAPAN etc) International collaboration (NOAA, INAMHI, LAPAN etc) Recent Research Focus Recent Research Focus Dehydration process in the TTL Dehydration process in the TTL Western/Central Pacific in N winter Western/Central Pacific in N winter Major Results Major Results Observational Evidences of Dehydration/Supersaturation in the TTL Observational Evidences of Dehydration/Supersaturation in the TTL Long-term variations in LS water Long-term variations in LS water Validations of AURA/MLS and SW Validations of AURA/MLS and SW Soundings of Ozone and Water in the Equatorial Region (SOWER) Fumio Hasebe, Hokkaido University f-hasebe@ees.hokudai.ac.jp A U.S.-Japan Workshop on the Tropical Tropopause Layer October 17, 2012 Future Plan Future Plan

2. Major Results Related to TTL Water TTL Dehydration TTL Dehydration Role of Kelvin- and Rossby-Wave Response to Convective Heating Associated with ISO (Eguchi and Shiotani, 2004) Role of Kelvin- and Rossby-Wave Response to Convective Heating Associated with ISO (Eguchi and Shiotani, 2004)

3. Major Results Related to TTL Water TTL Dehydration TTL Dehydration Spatiotemporal Characteristics (Hasebe et al., 2012) Spatiotemporal Characteristics (Hasebe et al., 2012) Minimum saturation mixing ratio along 7-day back trajectories Retain more water than SMR Lost water before the last 7 days Supersaturation beyond homogeneous necleation 350K: Out-flow from convective system. Both SMR min and OMR strongly depend on the regional convective activity (TR > BI > KT > SC). 360K: Air parcels usually retain more water than SMR min. In the midst of ‘cold trap’ dehydration. 380K: Appreciable portion of parcels still retains more water than SMR min, but the ‘cold trap’ dehydration is close to the final stage. 400K: The last dehydration event more than 7 days ago. The ‘cold trap’ dehydration is almost complete.

4. Major Results Related to TTL Water TTL Dehydration TTL Dehydration Water Vapor “Match” (Inai et al., 2012) Water Vapor “Match” (Inai et al., 2012) Multiple observations of water content for the same air parcel Multiple observations of water content for the same air parcel Lagrangian estimation of hydration/dehydration during advection Lagrangian estimation of hydration/dehydration during advection Careful screening procedure to exclude false match pairs Careful screening procedure to exclude false match pairs Inai et al. (2012)

5. Major Results Related to TTL Water TTL Dehydration TTL Dehydration Supersaturation/cirrus clouds (Shibata et al., 2007; 2012) Supersaturation/cirrus clouds (Shibata et al., 2007; 2012) Simultaneous lidar and CFH observations Simultaneous lidar and CFH observations Shibata et al. (2007) Bandung, Indonesia Dec. 16, 2004 CFH Flight Track Backscattering Ratio R

6. Major Results Related to TTL Water Long-Term Variation Long-Term Variation Long-Term Variation in Tropical LS Water (Fujiwara et al., 2010) Long-Term Variation in Tropical LS Water (Fujiwara et al., 2010) 68-37 hPa NOAA/FPH CFH SOWER CFH Ticosonde HALOE MLS

7. Future Plan Collaboration with ATTREX Collaboration with ATTREX Campaign Observations in January 2013 Campaign Observations in January 2013 Biak Water: CFH/FLASH/FineDew, Ozone: ECC, Lidar, Aerosol: OPC, Cloud Particles: HYVIS Biak Water: CFH/FLASH/FineDew, Ozone: ECC, Lidar, Aerosol: OPC, Cloud Particles: HYVIS Hanoi Water: CFH, Ozone: ECC Hanoi Water: CFH, Ozone: ECC Trajectory Forecast Trajectory Forecast Campaign Observations in January 2014 Campaign Observations in January 2014 Budget Proposal To Be Submitted (Deadline Nov. 1) Budget Proposal To Be Submitted (Deadline Nov. 1) Tarawa Tarawa Biak Biak Kototabang Kototabang Hanoi Hanoi Trajectory Forecast Trajectory Forecast Campaign Observations in July 2014 (?) Campaign Observations in July 2014 (?) Any Request? Any Request?  AOGS Annual Meeting (28 Jul - 1 Aug 2014) in Sapporo  AOGS Annual Meeting (28 Jul - 1 Aug 2014) in Sapporo

8. OPC Future Plan Optical Particle Counter (OPC) Optical Particle Counter (OPC) Size Distribution of Aerosols Size Distribution of Aerosols Hydrometeor Videosonde (HYVIS) Hydrometeor Videosonde (HYVIS) Microscopic View of Cloud Particles Microscopic View of Cloud Particles HYVIS

9. Future Plan Cryogenic Air Sampling Cryogenic Air Sampling Planed in 2015 (January?) Planed in 2015 (January?) Biak (?) Biak (?) Large Plastic Balloon Large Plastic Balloon Isotope Ratio Isotope Ratio Eastern Tropical Pacific Hakuho-Maru 2012 Watukosek, Indonesia 1992 JT Sampler

10. Future Plan Data Assimilation Data Assimilation Homogeneous 4D Dataset Accompanied by Error Estimates Homogeneous 4D Dataset Accompanied by Error Estimates ObservationModel DistributionNon-UniformUniform HomogeneityLowHigh ConsistencyLowHigh ErrorSmallLarge Advantages Advantages Detailed Description of Dehydration Processes Detailed Description of Dehydration Processes Dynamically consistent high resolution meteorological field Dynamically consistent high resolution meteorological field Observation Strategy Observation Strategy Optimum site allocation Optimum site allocation Optimum campaign period Optimum campaign period Key instruments Key instruments

11. Summary Science Questions Science Questions How the stratospheric water is determined How the stratospheric water is determined How such extreme super saturation realized How such extreme super saturation realized How tropospheric short-lived species enter stratosphere How tropospheric short-lived species enter stratosphere Key Instruments / Measurements Key Instruments / Measurements ECC Ozonesonde, Chilled-Mirror Frostpoint Hygrometers (CFH, FineDew), FLASH-B, OPC, HYVIS ECC Ozonesonde, Chilled-Mirror Frostpoint Hygrometers (CFH, FineDew), FLASH-B, OPC, HYVIS Cryogenic Air Sampling, Aerosol Sampling Cryogenic Air Sampling, Aerosol Sampling Data Assimilation Data Assimilation Locations and Date Locations and Date Western/Central Tropical Pacific Western/Central Tropical Pacific Tarawa, Biak, Kototabang, Hanoi Tarawa, Biak, Kototabang, Hanoi January 2013, 2014; July 2014(?) January 2013, 2014; July 2014(?) January 2015 January 2015 Budget not yet certain Budget not yet certain