Spatiotemporal Variability Relationships of Shallow Cloud Height and
Planetary Boundary Layer Height Over the Northeast Pacific Using
Satellite Observations and Reanalysis
Abstract
Over 18 years of satellite data from Multi-Angle Imaging
Spectroradiometer (MISR) and 14 years from Global Navigation Satellite
System-radio occultation (GNSS-RO), with ERA5 reanalysis temperature
profiles, are used to assess the co-variability of cloud and
thermodynamic properties of the Northeast Pacific subtropical marine
boundary layer. Low cloud top height (CTH) inferred from MISR and
planetary boundary layer height (PBLH) inferred from GNSS-RO are
well-correlated spatially for all seasons when seasonally-varying
mid-latitude grids (temperature at 700 hPa < 4°C) are removed
(r=0.83), or when vertical velocity at 500 hPa (ω500) indicates descent
(r=0.74). The temporal correlation of PBLH and CTH is highest in the
stratocumulus region (r=0.72), with the CTH versus PBLH slope close to
one for heights between 0.8 km and 1.6 km of the time series. Seasonal
sea-surface to 700 hPa lapse rate (LR) is spatially related with PBLH
and more strongly with CTH, and ω500 modulates seasonal CTH-LR
relationships. The impact of El Niño Southern Oscillation (ENSO) through
teleconnections on the PBL structure is also characterized, with maximum
deseasonalized temperature anomalies near or above PBL top (near the
surface) during La Niña (El Niño), with CTH, PBLH, and LR anomalies
largest during the strong 2015-2016 El Niño. Temperature anomalies above
the PBL lead CTH’ and PBLH’ by 15 and 18 months, respectively, just
under half the time scale of the periodicity of an Ocean Niño Index mode
(~3.1 years), suggestive of the role of
atmosphere-to-ocean exchange manifesting in a deepening PBL during warm
ENSO.