A Maloney Group, Weak Temperature Gradient Balance

Perspective

Precipitation is a strong increasing, non-linear function of lower free tropospheric humidity

Diabatic heating profile result of integrated effects

of cloud population and radiation

Diabatic heating structure

influences large-scale circulation

response

Large-scale circulation

response alters moisture field

MJO

????

SLHF OLR in

ERAi

import

neutral/

export

export

EddyMixin

g

What terms are dominant?

What is the phase relation of these terms?

Do the answers to these questions change dramatically

with location?

westerly mean statewest-east moisture

gradient

easterly mean stateeast-west moisture

gradient

easterlies poleward of

~7.5°

pole-equator moisture gradient

An Old Problem

Where is the MJO?

The RMM index only gives us a rough estimate

At what phase is the MJO “directly over” the DYNAMO domain?

How about TOGA-COARE?

A New Diagnostic

0°

90°

180°

270°

each gridpoint has its own “phase”

gridpoint phase

0°

90°

180°

270°

corresponds to RMM phase of maximum (+) MJO related anomaly in a variable

gridpoint phase

RMM phase

EX: for zonal wind this corresponds to maximum westerly winds

0°

90°

180°

270°

corresponds to RMM phase of maximum (-) MJO related anomaly in a variable

gridpoint phase

RMM phase

EX: for zonal wind this corresponds to maximum easterly winds

0°

90°

180°

270°

Tells you where you are in MJO lifecycle

gridpoint phase

RMM phase

45°prior to maximum (+) anomaly

0°

90°

180°

270°

Tells you where you are in MJO lifecycle

gridpoint phase

RMM phase

45°after maximum (+) anomaly

Identifies at what “RMM” phase <q> maximizes at each location

Objectively calculated from EOF structure

DYNAMO TOGA-COARE

Does it work?

Composites as a function of MJO lifecycle

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Point #1: Phasing Changes

Peak of convection

<q> (850-500)

October-April Column Integrated MSE Budget

RMM > 1

Composite as function of MJO lifecycle at each location using new diagnostic

MSE Composite Analysis

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Point #2: Phasing Matters

Point #3: Mean State Matters

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?

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Substantial cancelation in lat. average

Just after peak of convection

SLHF

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Near complete cancelation, all times, everywhere

Radiation Dominant….. Missing Physics?

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Horizontal Advection

SLHF

Point #4: In ERAi, horizontal advection drives tendency

Point #5: Local vs. large-scale processes at work

Zonal advection and SLHF are very large locally and correspond with intraseasonal OLR maxima, but are very weak in lat. average.

- Helps determine locations of maximum intraseasonal variance

Meridional advection is small locally and does not correspond with intraseasonal OLR maxima, but is very large in lat. average.

- Conditions tropics on large scale

Questions