Objectives
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MultiscaleinteractionsbetweentheMJO,equatorialwaves,andthediurnalcycleovertheMaritimeContinent
CarlJ.Schreck III1,Anantha Aiyyer1,Ademe Mekonnen21NorthCarolinaStateUniversity,2NorthCarolinaA&TUniversity
NASAPMMScienceTeamMeeting24–28October2016,HoustonTX
NASAPMMGrantNNX16AE33G
DiurnalCycleofConvection ForecastingConvectiveEnvelopes
MJO’spropagationacrosstheMaritimeContinentisamajorsubseasonal predictabilityproblem.
• HowdoequatorialwavesmodulatediurnalcycleofconvectionovertheMaritimeContinent?
• WhatroledoequatorialwavesplayintheMJO’stransitionacrosstheMaritimeContinent?
• HowwelldonumericalmodelsliketheCFSpredictequatorialwavesovertheMaritimeContinent?
ISCCP IR weather states (IR-WS) identify eight cloud regimes based on theircloud-top pressure (CTP) and their corresponding IR-regime in the ISCCP D1data. IR-WS1 (left) corresponds to well organized convection (i.e., MCS) andIR-WS3 (right) represents isolated cumulonimbus or cumulus congestusclouds. The diurnal cycles of these IR-WS data will be compared with TRMMPrecipitation Feature (PF) data over the Maritime Continent.
Hypothesis1:• LiketheMJO,equatorialwaves
favorupscalegrowthofconvection• However,theirshorterperiods
reducetheinteractionwiththediurnalcycle
Task1:• Identifythediurnalcycleof
convectionineachphaseofKelvinandEquatorialRossby waves
• CompareresultswithISCCP,TRMMPF,andTRMM/IMERGrainfall
Hypothesis2:• Thepopulationofequatorialwaves
dictateswhichMJOeventstraversetheMaritimeContinent
• Beinglesssensitivetothediurnalcycle,equatorialwavesprovideabridgefortheMJO
Task2:• Comparewavevariancebetween
MJOsthatdoordonotpropagateacrossMaritimeContinent
Hypothesis3:• TheCFSismoreskillfulat
forecastingtheconvectiveenvelopesoftheMJOandequatorialwavesthanactualrainfall
Task3:• FilterCFSReforecastto
createretrospectiveforecastsofOLRandrainfall
• Examineanomalycorrelationswithobserveddata
Hypothesis4:• TheCFSskillatforecasting
theMJO,equatorialwaves,andthediurnalcycleareallcorrelatedwitheachother
Task4:• Identifygoodandbad
forecastsoftheMJOovertheMaritimeContinent
• Comparethewaveactivity,waveforecasts,anddiurnalcyclesbetweeneach
Hovmöller oftotalrainfall(shading).MJO(blue),equatorialRossbywaves(magenta),andKelin waves(red)arecontoured.Vertical
dashedlinesoutlinetheMaritimeContinent
Homoller countsofISCCPWeatherStates(WS)ofMCSs(left)anddisorganizedconvection(right).
ExampleforecastHovmöllers ofOLRanomalies(shading)andfilteredwavemodes.(left)Observationsareappendedwithclimatologicalvaluesforfiltered(WheelerandWieckmann 2000).(right)ObservationsareappendedwithCFS
forecasts.
ncics.org/mjo
