Temperature and Lapse Rate Changes Over the IPCC Regions and Over Large-Scale Zonal Bands

Transcription

1 Atmospheric Remote Sensing and Climate System Research Group A R S C l i S y s Temperature and Lapse Rate Changes Over the IPCC Regions and Over Large-Scale Zonal Bands I. Thaler, U. Foelsche, G. Kirchengast, B. Lackner, B. Pirscher Wegener Center for Climate and Global Change (WegCenter) and Institute for Geophysics, Astrophysics and Meteorology, Inst. of Physics, University of Graz, Austria / Klimatag / 03/11/2010

2 1 Data Sources and Data Description Climate Model Simulation Data Radio Occultation Data 2 Lapse Rate Change Over the IPCC + Regions IPCC + Region Definition Lapse Rate and Atmospheric Stability Lapse Rate Change in the Upper Troposphere Lapse Rate Change Between 8 km and Surface 3 Temperature and Lapse Rate Over Central North America (CNA) Temperature and Lapse Rate Time Evolution Temperature and Lapse Rate Time Evolution Conclusions 2 / 14

3 Climate Model Description Figure: IPCC Temperature Projections Used model: GCM ECHAM5 developed at Max Planck Institute for Meteorology in Hamburg Used scenario: A2 Self-reliant nations Increasing population Regionally oriented economic development Slower technological development Taken from AR4, IPCC / 14

4 Radio Occultation Data Retrieval Process Figure: Radio Occultation Retrieval Process Two satellites in limb sounding mode (LEO and GPS) Vertical scanning through relative movement to each other Bending angle = refractivity = temperature Taken from the Geodetic Data Archive Facility, Agenzia Spaziale Italiana 4 / 14

5 Radio Occultation Data Temperature Profile Figure: Radio Occultation Temperature Profile Dry temperature: neglecting contribution of water vapor to refractivity 5 / 14

6 IPCC + Region Definition Figure: IPCC + Regions Taken from Bettina Lackner et al. (2009), Trend Indicators of Atmospheric Climate Change Based on Global Climate Model Scenarios 6 / 14

7 Lapse Rate and Atmospheric Stability Dry Adiabatic LR (DALR) dt dz = g c p = 9.8 K/km Saturated Adiabatic LR (SALR) dt dz = g c p + L c p dm * dz = 9.8 K/km (2 to 6) K/km Figure: Atmospheric Stability Criteria Taken from Dave Gardiner (2009), Atmospheric Thermodynamics 2 and Dynamics Stability Criteria unstable (ELR1): ELR > DALR cond. unstable (ELR2): DALR > ELR > SALR stable (ELR3): MALR > DALR > ELR 7 / 14

8 Lapse Rate Change in the Upper Troposphere LR decrease: most regions LR increase: high latitude and some mid latitude regions 8 / 14

9 Lapse Rate Change Between 8 km and Surface LR decrease: most regions LR increase: some high altitude regions 9 / 14

10 Annual CNA Temperature Anomaly Projections Tdry at 10 km and 8 km similar Tphys at 10 km and 8 km similar Surface T changes less than at high altitudes 10 / 14

11 Annual CNA Lapse Rate Anomaly Projections LR upper troposphere: small variations, LRdry and LRphys similar LR between 8 km and surface: both large variations, decreasing LR decrease all over: higher atmospheric stability 11 / 14

12 Observed Monthly CNA Lapse Rate Change 12 / 14

13 Conclusions 20C3M/A2 scenario Lapse rate increase (higher atmospheric instability) through whole troposphere: high latitude regions Lapse rate decrease between 0 km and 8 km; non-significant increase in upper troposphere: some mid-latitude regions Lapse rate decrease (higher atmospheric stability) throughout the whole troposphere: most other regions (e.g. CNA) Different data sets from For detecting any significant trend in temperature or lapse rate evolution the time period is too short 13 / 14

14 Thank you TIME FOR QUESTIONS! 14 / 14