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On the instantaneous linkages between cloud vertical structure and large -scale climate

On the instantaneous linkages between cloud vertical structure and large -scale climate . Ying Li Colorado State University. Data: . Merged CALIPSO / CloudSat data ( 2B-GEOPROF-LIDAR product; June 2006–April 2011 ) cloud incidence is derived from cloud fraction

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On the instantaneous linkages between cloud vertical structure and large -scale climate

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  1. On the instantaneous linkages between cloud verticalstructure and large-scale climate Ying Li Colorado State University

  2. Data: • Merged CALIPSO/CloudSat data • (2B-GEOPROF-LIDAR product; June 2006–April 2011) • cloud incidence is derived from cloud fraction • e.g., 25% indicates a cloud is observed 25% of the time within the sample volume • Meteorological fields obtained from 1) Collocated CloudSat ECMWF-AUX auxiliary data product • –instantaneousrelationships (∼108 profile measurements) • 2) ERA-Interim reanalysis • – in some selected cases • – month-to-month variability (∼105monthly-mean profile measurements)

  3. A range of large-scale meteorological parameter 1. sea surface temperature (SST) 2. lower tropospheric stability (LTS; θ3km − θsurface) 3. mid-tropospheric vertical motion (−ω500) 4. storm track activity：RMS (ω’500) 5. tropopause temperature (TT) 6. upper tropospheric stability (UTS; θtropopause − θtropopause−3km)

  4. The role of stratospheric wave driving in linking the TT and UTS, and space/time distribution of upper tropospheric cloud incidence Cold tropopause Weak static stability Lift of tropopause Increased cloud incidence From Li and Thompson (JGR, 2013)

  5. A range of large-scale meteorological parameter 1. sea surface temperature (SST) 2. lower tropospheric stability (LTS; θ3km − θsurface) 3. mid-tropospheric vertical motion (−ω500) 4. RMS (ω’500) and dT/dy in the storm track region 5. tropopause temperature (TT) 6. upper tropospheric stability (UTS; θtropopause − θtropopause−3km)

  6. Vertical structure of cloud incidence as a function of SST over the Global Ocean Peak at 303 K Minimum 295-300 K Maximum below 285 K Shallow maximum 272 – 278 K Increase with decreasing SST e.g., Klein and Hartmann 1993; Wood and Bretherton, 2006 Mid/high lat. regime

  7. SST between 272 – 286K SST between 272 – 286K

  8. A range of large-scale meteorological parameter 1. sea surface temperature (SST) 2. lower tropospheric stability (LTS; θ3km − θsurface) 3. mid-tropospheric vertical motion (−ω500) 4. RMS (ω’500) and dT/dy in the storm track region 5. tropopause temperature (TT) 6. upper tropospheric stability (UTS; θtropopause − θtropopause−3km)

  9. Influences of lower tropospheric stability Maximum at low LTS e.g., stratus associated with extratropical synoptic storms) Maximum at high LTS e.g., stratocumulus clouds Height (km) Dual maxima: different types of clouds throughout the mid/high latitude

  10. A range of large-scale meteorological parameter 1. sea surface temperature (SST) 2. lower tropospheric stability (LTS; θ3km − θsurface) 3. mid-tropospheric vertical motion (−ω500) 4. RMS (ω’500) and dT/dy in the storm track region 5. tropopause temperature (TT) 6. upper tropospheric stability (UTS; θtropopause − θtropopause−3km)

  11. Influences of mid-tropospheric vertical motion Increases as w 1% per 10 hPa d-1 High-top clouds tends to occur in regions of rising motion/low pressure Height (km) Low-top clouds tends to occur in regions of sinking motion/high pressure • Bimodal vertical distribution is due to: • Passage of the cloud frontal system (low-level clouds behind the cold frons are associated with upper-level clouds ahead of the cold front) • Superpostion of alternating cyclonic and anticyclonic weather systems

  12. Vertical structure of the linkages between anomalous cloud incidence and vertical motion over the extratropical ocean (30-90S/N) Regions of anomalously upward motion are associated with anomalous high cloud incidence ~3% per 10 hPa d-1 Height (km)

  13. A range of large-scale meteorological parameter 1. sea surface temperature (SST) 2. lower tropospheric stability (LTS; θ3km − θsurface) 3. mid-tropospheric vertical motion (−ω500) 4. RMS (ω’500) and dT/dy in the storm track region 5. tropopause temperature (TT) 6. upper tropospheric stability (UTS; θtropopause − θtropopause−3km)

  14. Cloud incidence in the combined four storm track regions • Peak at jet stream level & Increases with increasing storm track amplitude • e.g., nimbostratus, deep convective clouds Low level clouds decease with increasing storm track amplitude

  15. A range of large-scale meteorological parameter 1. sea surface temperature (SST) 2. lower tropospheric stability (LTS; θ3km − θsurface) 3. mid-tropospheric vertical motion (−ω500) 4. RMS (ω’500) and dT/dy in the storm track region 5. tropopause temperature (TT) 6. upper tropospheric stability (UTS; θtropopause − θtropopause−3km)

  16. Influences of tropopause temperature (TT) and upper tropospheric stability (UTS) Increases as UTS decreases ~8% per K km-1) Increases as TT decreases (1.5-2% K-1)

  17. Vertical structure of the linkages between anomalous cloud incidence and static stability over the extratropical ocean (30-90S/N) Regions of anomalously low static stability are associated with anomalous high cloud incidence ~2% per K km-1

  18. Summary • The results in study • provide a baseline for evaluating physical parameterizations of clods in GCM • serve as a reference for interpreting the signature of large-scale atmospheric phenomena in cloud vertical structure Li, et al (GRL, 2014)

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