Variations in CERES-Terra
Fluxes and Cloud Properties with
Zach Eitzen (SSAI/NASA-LaRC)
Kuan-Man Xu (NASA-LaRC)
Takmeng Wong (NASA-LaRC)
• Thanks to David Doelling and Michele
Nordeen for help with CERES cloud
• Recent authors (e.g., Wagner et al. (2008,
Atmos Chem Phys) have used satellite data to
examine cloud properties and their changes with
• Others (e.g., Bony et al. 2004, Klein and
Hartmann 1993, Wood and Bretherton 2006)
have studied how clouds change with dynamical
regime and lower-tropospheric stability.
• Here, we look at changes in cloud properties
with SST anomaly, and attempt to quantify the
portion of that change that is due to shifts in
stability within a given dynamical regime.
• All data is from March 2000-Feb 2005.
• Monthly mean 1x1 degree CERES-EBAF data is used
for radiative fluxes.
• Monthly mean 1x1 degree CERES Terra SRBAVG Non-
GEO data is used for optical depth and cloud fraction
and cloud top height.
• Monthly mean Reynolds SSTs from NOAA.
• ECMWF-Interim data is used for meteorological data,
including w700 and Estimated Inversion Strength (EIS).
• “Standard” anomalies are calculated by subtracting each
month’s value from the five-year mean for that month.
• Residual anomalies of cloud and radiative properties are
calculated by taking the mean anomaly associated with a
given (w700, DEIS) state and subtracting it from the
Change in total cloud fraction with SST (%/K)
Change in ln(tau) with SST (K-1)
Change in LW CRE with SST (W m-2 K-1)
Change in SW CRE with SST (W m-2 K-1)
Change in Net CRE with SST (W m-2 K-1)
Low cloud regions from Jensen et al. (2008)
Frequency of DEIS-w700 regimes
Average low cloud anomalies
Joint distribution of low cloud
fraction and SST anomalies
Average low cloud ln(t) anomalies
Average SW CRE anomalies
Average Net CRE anomalies
Changes in properties with SST
Property Slope with standard Slope with residual
Low Cloud Fraction -4.4 % K-1 -1.8 % K-1
Low Cloud ln(t) -0.103 K-1 -0.049 K-1
LW CRE 1.3 W m-2 K-1 0.5 W m-2 K-1
SW CRE 3.4 W m-2 K-1 2.1 W m-2 K-1
Net CRE 4.7 W m-2 K-1 2.6 W m-2 K-1
• Near the ITCZ, cloud top heights, cloud fraction
and cloud optical depth all increase with SST,
leading to little change in net CRE.
• In subtropical boundary-layer cloud regions,
cloud fraction and cloud optical depth decrease
with SST, leading to less shortwave cooling.
• Changes in cloud and radiative properties with
SST have a strong association with changes in
EIS within each dynamical regime, but there
appears to be a positive cloud feedback even
after this is removed.
• Look at additional fields.
• Filter out months with too much high cloud
• Look at individual regions.
Change in cloud top height with SST (km/K)
Frequency of DEIS-Dw700 regimes
Average LW CRE anomalies
Joint distribution of low cloud ln(t)
and SST anomalies
Joint distribution of SW CRE and
Joint distribution of LW CRE and
Joint distribution of Net CRE and