Cloud-Radiative Driving of the Madden-Julian Oscillation as Seen by the A-Train

Tony Del GenioYonghua Chen

, CloudSat/CALIPSO Meeting, 11/3/14

(Flato et al. 2014, IPCC AR5 WG1, Chapter 9)

The MJO:

- Many independentstudies that agree

- High-quality obs

- The models areterrible

- They haven’t gottenbetter in a decade

What makes the MJO? (from Adam Sobel’s 2013 EUCLIPSE lecture)

Let h = moist static energy = cpT + gz + Lq (vertically integrated)S = sources and sinks of h (advection, surface fluxes, radiation)

So dh/dt = S; this is called a “moisture mode”

(depends on sensitivity of convection to moisture)

(depends on correlation of radiative heating or surface evaporation with precip)

10 MJOs,2006-2010

GEOPROF-LIDAR GISS GCM, DYNAMO

No MJO

Good MJO

ECMWF-AUX inputs intoFLXHR-LIDAR heatingappear to be reasonablefor MJO anomalies

OLR a good proxy for net heating anomaly; largest in Indian Oceanand ~5 days in advance of MJO peak

Maximum radiative heating anomaly occurs beforeMJO peak, but positive anomalies continue long after

precipitation returns to normal

peak

s

time

SW anomaly mostly opposes LW, but both stabilize onset region

FLXHR-LIDAR minus FLXHR heating differences vs. MJO phase – thin cirrus matter to onset phase

- Magnitude of observed OLR, rain anomalies comparable to that in good MJO models for 2009 YOTC Event E hindcast

- Strong OLR’-P’ correlation supports idea of cloud-radiative driving of MJO

ISCCP-TMI

(good MJO)

(no MJO)

Summary• GEOPROF-LIDAR convection depth vs. AMSR-E CWV appears to

be a good metric for GCM cumulus parameterizations; consistent with moisture mode ideas about MJO eastward propagation

• OLR a good proxy for total column radiative heating anomaly, but SW absorption affects the profile and reinforces upper level heating near MJO onset

• Cirrus heating also appears to play a role before MJO onset (Kelvin waves?)

• Cloud-radiative feedback likely to be the driver of the MJO; well correlated with precipitation anomalies, though cloud anomalies persist as rain decreases

• It is now possible for GCMs to make MJOs, and even perhaps for the right reason