dynamo—dynamics of the mjo shipboard operation of the nasa/toga radar dynamo—dynamics of the mjo...
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DYNAMO—DYNAmics of the MJOShipboard operation of the NASA/TOGA radarDYNAMO—DYNAmics of the MJOShipboard operation of the NASA/TOGA radar
Photo courtesy of T. LangPhoto courtesy of T. Lang
September 2011 – February 2102
Moum et al. 2014
SST patternquiteinteresting!Ocean reallynever “recovered” after MJO2.
Prolonged periods (> 24 hours) ofnegative net flux rare in tropics. Theseare periods when ocean cools throughloss of latent and sensible heat (SST> Tair)and reduction in solar insolation. This is part of the story!
SST
AIR
Strong westerlies in MJO2
Yoshida-Wyrtki jet, westerly surface current.
Yoshida-Wyrtki jet, westerly surface current.
Mixing promoted by strong vertical shear brings cool, salty water to the surface.
Shear induced mixing is significant component for lowering the SST’s,in addition to surface fluxes/insolation. MJO2 resulted in a major cooling of the upper ocean. Did this have an impact on MJO3, which was muchweaker?
Shallow thermocline in Indian O. allows access to cooler water.
Mixing promoted by strong vertical shear brings cool, salty water to the surface.
Shear induced mixing is significant component for lowering the SST’s,in addition to surface fluxes/insolation. MJO2 resulted in a major cooling of the upper ocean. Did this have an impact on MJO3, which was muchweaker?
Shallow thermocline in Indian O. allows access to cooler water.
Moum et al. 2014
Daily Evolution: Convective Population
1. In phase:
RH, Rainrate,
Strat. Rain.
2. In phase:
SST, Lightning,
CAPE.
Role of Aerosols?
A little background…
Z
Kdp
Oklahoma
Kdp proportional to mass content andmass-weighted oblateness ratio
Based on computationsof Z and Kdp from DSDassumptions
Based on computationsof Z and Kdp from DSDassumptions
0.5 deg elevation angle0.5 deg elevation angle
50
40
30
2 4 6
deg/km Difference in H,V phase in degrees
RainRain
Kdp is a measure of the difference in wave propagation between H and V polarizations; sensitive to non-spherical particles
a
b
0
Differential Reflectivity
Reflectivity
N-Pol in Oklahoma
Results consistent withactive coalescence growthand ice-based precipitation.
Resulting from highermoisture contents, higherfreezing level, collisionalbreakup, etc.
N-Pol data are clearly goingto help us better understandDSD variability and the physics leading to the variability.
N-Pol in Oklahoma
Results consistent withactive coalescence growthand ice-based precipitation.
Resulting from highermoisture contents, higherfreezing level, collisionalbreakup, etc.
N-Pol data are clearly goingto help us better understandDSD variability and the physics leading to the variability.
Colorado and “tropical”eventsColorado and “tropical”events
Warm rainWarm rain
Ice basedIce based
Normalized density of points expressed as a percentageNormalized density of points expressed as a percentage
N-POLN-POL
26 Jan 1999 EAST case.Stronger convection,higher CAPE.
24 Feb 1999WEST case.Lower CAPE,monsoon-like regime.
EAST WEST
0
SubtledifferencesbetweenEast andWest
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