Planetary Boundary Layer Height and Cloud-top-height from COSMIC and CALIPSO over Eastern Pacific Ocean Feiqin Xie Texas A&M University – Corpus Christi, TX Coauthors: D. L. Wu (GSFC), R. Wood (Univ. Washington) Acknowledgement: C. O. Ao, A.J. Mannucci and J. Teixeira (JPL) 8th FORMOSAT3/COSMIC Workshop October 2, 2014 Marine Planetary Boundary Layer Clouds GOES Trade cumuli Stratocumulus Transition Bottom photographs courtesy of Dr. Bjorn Stevens Why Planetary Boundary Layer? Courtesy of Prof. R. Wood, Univ. of Washington ² Key component of the weather and climate system, Interface between earth’s surface and the free troposphere (affect energy and mass flux) ² Governing the evolution of low clouds (large uncertainty in climate feedback according to IPCC-2007/2013 report) Different PBL Vertical Structure Lock et al., 2000, MWR VOCALS 2008 (Oct-Nov) VAMOS Ocean-Cloud-Atmosphere-Land Study Radiosonde COSMIC Xie. et al., ACP, 2012 VOCALS PBL Structure (Radiosonde) Stratus-topped PBL Courtesy of Prof. R. Wood Univ. of Washington The inversion-base height is consistent with Cloud-top-height Lower boundary layer height à lower clouds Near-coincident VOCALS PBL Case Radiosonde/GPSRO/ECMWF Near-coincident VOCALS PBL Case Radiosonde/GPSRO/ECMWF Near-coincident VOCALS PBL Case Radiosonde/GPSRO/ECMWF Xie, et al., 2012 ACP Near-coincident COSMIC vs. CALIPSO (<18min apart) 18S COSMIC/RO 20S 22S CALIPSO 24S 26S GOES 78W 76W 74W 72W COSMIC vs. CALIPSO Near-coincident COSMIC vs. CALIPSO Bending Angle (<18min apart) 18S COSMIC/RO ECMWF 20S 22S Refractivity Gradient CALIPSO 24S GOES ECMWF 26S 78W 76W 74W 72W Cloud-Top-Height ~1km (21.7S, 74.1W) CALIPSO (lidar) 0 30S 90W 45W DJF MAM GPS PBLMRG CALIPSO CTH 2006-2011 20062010 JJA GPS PBL height is consistent with CALIPSO cloud-topheight over subtropical eastern oceans SON Cloud-Top-Height vs. PBL Height CALIPSO-CTH COSMIC-PBLH PBLH-CTH DJF MAM ! Cloud-Top-Height vs. PBL Height CALIPSO-CTH COSMIC-PBLH PBLH-CTH JJA SON ! Seasonal Mean Precipitation (mm/day) DJF MAM Strong SPCZ JJA Xie&Arkin BAMS, (1997) SON Weak SPCZ Near-coincidence: cosmic & radiosonde Temperature Refractivity −dN/dz [km-1] q cosmic rds Hawaii Bending RH rds cosmic rds Near-coincidence: cosmic, radiosonde & ecmwf Temperature Refractivity rds q −dN/dz [km-1] ecmwf Hawaii RH Bending rds ecmwf cosmic Conclusions • GPS RO signal is very sensitive to the sharp moisture gradient beneath the inversion (PBL top). • COSMIC RO PBL height is highly consistent with CALIPSO cloud-top-height over subtropical eastern oceans. • Relative large discrepancy is found over ITCZ and SPCZ regions due to convection and weak PBL inversion. • Decoupled PBL could lead to discrepancy between thermal inversion height and CTH. • Refractivity gradient is more sensitive to moisture gradient than temperature inversion. The gradient method could thus lead to detection of shallow mixing layer instead of the trade inversion. Acknowledgement • NASA-NRA-NNH13ZDA001N-TERAQ • NSF-1015945. Special thanks to Anjuli S. Bamzai & Eric DeWeaver • JPL GPS operational team: B. Iijima, M. Pestanal, T. Meehan and L. E. Young for COSMIC RO soundings. • UCAR COSMIC Group for UCAR COSMIC retrievals • ECMWF/ERA-interim data • Texas A&M University – Corpus Christi • Coastal and Marine System Science PhD Program at TAMUCC. • Contact: [email protected]
© Copyright 2024 ExpyDoc
