TY - JOUR
T1 - Lagrangian evolution of the northeast pacific marine boundary layer structure and cloud during CSET
AU - Mohrmann, Johannes
AU - Bretherton, Christopher S.
AU - McCoy, Isabel L.
AU - McGibbon, Jeremy
AU - Wood, Robert
AU - Ghate, Virendra
AU - Albrecht, Bruce
AU - Sarkar, Mampi
AU - Zuidema, Paquita
AU - Palikonda, Rabindra
N1 - Funding Information:
Acknowledgments. The authors gratefully acknowledge the entire CSET team, and Peter Blossey and Ryan Eastman for insightful discussions. We are also very grateful to the anonymous reviewers for their feedback, which have been helpful in improving this paper. We also acknowledge ECMWF for provision of ERA5 data, and NOAA ARL for provision of the HYSPLIT model. This work was supported by NSF Grants AGS-1445813, AGS-1445832, and AGS-1660609. V. Ghate was supported by the National Science Foundation (NSF) Grant AGS-1445831 awarded to the University of Chicago and the U.S. Department of Energy’s (DOE) Atmospheric System Research (ASR), an Office of Science, Office of Biological and Environmental Research program, under Contract DE-AC02-06CH11357 awarded to Argonne National Laboratory. McCoy was supported by the NSF Graduate Research Fellowship Program under Grant DGE-1762114. CSET campaign data, including trajectories, may be found at the CSET Data Archive (https:// data.eol.ucar.edu/master_list/?project5CSET).
PY - 2019
Y1 - 2019
N2 - Flight data from the Cloud System Evolution over the Trades (CSET) campaign over the Pacific stratocumulusto- cumulus transition are organized into 18 Lagrangian cases suitable for study and futuremodeling,made possible by the use of a track-and-resample flight strategy. Analysis of these cases shows that 2-day Lagrangian coherence of long-lived species (CO and O3) is high (r = 0.93 and 0.73, respectively), but that of subcloud aerosol,MBL depth, and cloud properties is limited. Although they span a wide range in meteorological conditions, most sampled air masses show a clear transition when considering 2-day changes in cloudiness (-31% averaged over all cases),MBL depth (+560m), estimated inversion strength (EIS; -2.2K), and decoupling, agreeing with previous satellite studies and theory. Changes in precipitation and droplet number were less consistent. The aircraft-based analysis is augmented by geostationary satellite retrievals and reanalysis data along Lagrangian trajectories between aircraft sampling times, documenting the evolution of cloud fraction, cloud droplet number concentration, EIS, andMBL depth. An expanded trajectory set spanning the summer of 2015 is used to show that the CSET-sampled air masses were representative of the season, with respect toEIS and cloud fraction. TwoLagrangian case studies attractive for future modeling are presented with aircraft and satellite data. The first features a clear Sc-Cu transition involving MBL deepening and decoupling with decreasing cloud fraction, and the second undergoes a much slower cloud evolution despite a greater initial depth and decoupling state. Potential causes for the differences in evolution are explored, including free-tropospheric humidity, subsidence, surface fluxes, and microphysics.
AB - Flight data from the Cloud System Evolution over the Trades (CSET) campaign over the Pacific stratocumulusto- cumulus transition are organized into 18 Lagrangian cases suitable for study and futuremodeling,made possible by the use of a track-and-resample flight strategy. Analysis of these cases shows that 2-day Lagrangian coherence of long-lived species (CO and O3) is high (r = 0.93 and 0.73, respectively), but that of subcloud aerosol,MBL depth, and cloud properties is limited. Although they span a wide range in meteorological conditions, most sampled air masses show a clear transition when considering 2-day changes in cloudiness (-31% averaged over all cases),MBL depth (+560m), estimated inversion strength (EIS; -2.2K), and decoupling, agreeing with previous satellite studies and theory. Changes in precipitation and droplet number were less consistent. The aircraft-based analysis is augmented by geostationary satellite retrievals and reanalysis data along Lagrangian trajectories between aircraft sampling times, documenting the evolution of cloud fraction, cloud droplet number concentration, EIS, andMBL depth. An expanded trajectory set spanning the summer of 2015 is used to show that the CSET-sampled air masses were representative of the season, with respect toEIS and cloud fraction. TwoLagrangian case studies attractive for future modeling are presented with aircraft and satellite data. The first features a clear Sc-Cu transition involving MBL deepening and decoupling with decreasing cloud fraction, and the second undergoes a much slower cloud evolution despite a greater initial depth and decoupling state. Potential causes for the differences in evolution are explored, including free-tropospheric humidity, subsidence, surface fluxes, and microphysics.
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U2 - 10.1175/MWR-D-19-0053.1
DO - 10.1175/MWR-D-19-0053.1
M3 - Article
AN - SCOPUS:85077495978
VL - 147
SP - 4681
EP - 4700
JO - Monthly Weather Review
JF - Monthly Weather Review
SN - 0027-0644
IS - 12
ER -