BorneoVortex:Multiscalarinteractions.(UM)

A.A.Samah,OoiSeeHai,FadzilMohd.NorandKumaren

The global influenceTheglobalinfluence.

TheSiberianHigh:

1. Arctic Oscillation.1. ArcticOscillation.

2. ENSO

Methodology

ClimatologyMSLP&ATcalculatedbyaveragingmonthlydatafrom19712000

SiberianHighIndexwascalculatedbyfindingout the maximum daily (from 6 hourly NC file)outthemaximumdaily(from6hourlyNCfile)andthenaveraged(ofthedailymaxvalues)formonthlyvalue.o o t y a ue

SiberianHighareadefinedat800 1200 E,400 600 N60 N

SiberianHighClimatology

Siberian High Index (SHI)SiberianHighIndex(SHI)

AveragedofdailymaximumMSLPoverdefinedAveraged of daily maximumMS P over definedarea(800 1200 E,400 600 N).

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Xn.m isthevalueofaveragedmaxofSLPatmonthm, yearn;

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istheclimatologyaverage(19712000)ofmonthlyaverageofmaximummeanSLPformonthm,

is its climatology standard deviation at monthm.

mX

m isitsclimatologystandarddeviationatmonthm.

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SiberianHighIndex(yearly)ofAreaAveragedandMaximumAveraged

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Fig.1: Yearly averaged Siberian high index(SHI AAVE) - an index calculated by averaging the mean SLP values over the defined area (80-1200E,40-60 0N ) and (SHI AvdMx) by averaging the daily maximum mean SLP over the same

defined area. Correlation coefficient : 0.89defined area. Correlation coefficient : 0.89

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Fig.2: NDJFM averaged Siberian High Index (SHI Area Ave)- light blue and Siberian High Index (SHI Max Ave) black line over the same defined area.

Correlation coefficient : 0.91

ArcticOscillationandSiberianHighArcticOscillation

NonseasonalSLPvariationsnorthof200N,characterizedbySLPanomaliesofonesignintheArcticandanomaliesofoppositesignin mid latitude centered about 37450N (Thompson and Wallaceinmidlatitude,centered about37 45 N(ThompsonandWallace(1998).

Fig. 3. Arctic Oscillation phases and its influence over northern hemisphere (photo courtesy: http://www.appinsys.com/GlobalWarming/AO_NAO.htm and J Wallace, Univ. of Washington).

Result:ArcticOscillationandSiberianAirTemperature

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Fig.4:ArcticOscillationandairtemperatureanomalies(801200E,40600N)d NDJFM

AOI(NDJFM) AirTempanom(aveNDJFM)

averagedoverNDJFM.

Correlationcoefficient:0.65

AirTemperatureduringAOPositiveandNegative

Fig.5:(left)AirtemperaturesatSiberianhighareaareabovetheaveragetemperatureduringAOpositivephase.

( i h ) Ai Sib i l [ ld ] h d i(right)AirtemperaturesoverSiberianareaarelower[colder]thanaverageduringAOnegativephase.

AirTemperatureandSHI

SHI d Ai T t A li (NDJFM )

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Fig.6.RelationshipbetweenSHIanddefinedSHareaairtemperature.Astheairtemperaturelower,theSHIvalueishigher.

Correlation coefficient is 0.56Correlationcoefficientis 0.56

ArcticOscillationandSealevelPressure

Fig. 7: SLP anomalies during 2 phases of AO. (left) SLP anomalies during positive AO. TheFig.7:SLPanomaliesduring2phasesofAO.(left)SLPanomaliesduringpositiveAO.TheSLPoverSiberianhighareaarerelativelylowerthanaverage.

(right)SLPanomaliesduringnegativeAO.TheSLPovertheSiberianhighisrelativelyhigherthanaverage.

AOIandSHI

SiberianHighIndexandArcticOscillation(aveNDJFM)

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Fig.8.:Winteraverage(NDJFM)SiberianhighindexandAOindex

( l i ffi i 0 51)

SHI AOI

(correlationcoefficient=0.51)

ENSO and SHIENSOandSHI

ENSOandSiberianhighENSOENSO

ElNinoLaNina

Fig. 9: Effects on weather during boreal winter (for El Nino and La Nina phases). (photo courtesy : http://www.srh.weather.gov/srh/jetstream/tropics/enso_impacts.htm)

SiberianAirtemperatureandENSOphases

Fig.10.(above)Airtemperatureg ( ) panomaliesduringElNioyears(below)airtemperaturesanomaliesduringLaNiayears.

SiberianAirtemperatureandSOI

SOI and Air Temperature anomalies over defined Siberian high area (averaged NDJFM)

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Fig.11.SiberianairtemperatureandSOI.ThevaluesareNDJFMaveraged.TheairtemperaturedataandSH

indexwillbetestwithSOIfromhereafter.

SLPandENSOPhases

Fig.12.compositeofSLPanomalies(averagedNDJFM)duringstrongElNioyears(1972,1982,1991,1997).

Fig.13.SLPanomalies(averagedNDJFM)duringstrongLaNiayears(1973,1975,1988).

Corr. Between SOI and SHI.

CorrelationofaveragedvalueofSHIandSOI(MAMMarchAprilMay;JJAJuneJulyAugust;SON SeptemberOctoberNovember;DJF December,JanuaryFebCorrelationofaveragedvalueofSHIandSOI(NDJF NovemberDecemberJanuaryFebruary;MAMJ MarchAprilMayJune;JASO JulyAugustSeptemberOcto

Corr.BetweenSOIandSHI.

SHI\SOI MAM JJA SON DJFMAM 0.17 0.07 0.12 0.15

JJA 0.47 0.41 0.36 0.32SON 0.23 0.37 0.51 0.49DJF 0.23 0.10 0.10 0.26

\SHI\SOI NDJF MAMJ JASONDJF 0.10 0.03 0.13

MAMJ 0 28 0 28 0 15MAMJ 0.28 0.28 0.15JASO 0.31 0.45 0.43

Synoptic and Mesoscale influence.SynopticandMesoscaleinfluence.

IntroductiontothegeneralclimatologyofMalaysia.g gy y IntroductiontotheWinterMonsooninSouthEastAsia. ColdSurgesandBorneoVortex. SynopticSignature. Observationalcasestudies. WRFSimulations. DiagnosticstudyonimpactofBorneoVortexConvectionson

the General CirculationstheGeneralCirculations.

Conclusion.

Researchofmygroupinthisarea.

1.ClimatologyoftheColdSurgeandBorneoVortex(NCEP)

2 I i Ob i l k2.IntensiveObservationalwork.

3.ModelsimulationsusingWRF.

CLIMATOLOGICAL STUDIES (NCEP)CLIMATOLOGICALSTUDIES(NCEP)

Formation of Cold Surges and Borneo Vortex isFormationofColdSurgesandBorneoVortexisrelatedtomidlatitudeforcing.

Development and troughing of the Siberian DevelopmentandtroughingoftheSiberianHighandcoldsurgesinSCS.

JJAJJA

ND

JFJF

A case study ofA case study of CS and BVBefore Surge

A l i f 00 UTC (t l ft) 500 hP h i h i h i ht [i dk t 60Analysis of 00 UTC (top left) 500 hPa hemispheric height [in dkm, at 60-mcontour intervals], (top right) hemispheric mean sea level pressure [in hPa, withselected pressure values], (bottom right) 925-hPa wind with shaded magnitudes >=20 knots and positive relative vorticity (dashed lines, x 10 -4 sec -1 )

During Surge

During Surge With Cross Equatorial FlowDuring Surge With Cross Equatorial Flow Intensification

Figure 5: Average sea surface temperature (o C) for the period 12 19 January20102010.

ColdSurgesandBorneoVortexandDeepOrganisedConvection.

The meso-scale to local scale interactions between wind, sea and topography

Driving Force of the Study of CSDrivingForceoftheStudyofCSandBorneoVortexisthe

developmentofDeepOrganisedand Sustained Convections inandSustainedConvectionsin

MalaysiaandIndonesia.

Borneo Vortex Study.

09012009 at 0230Z Star dated 18 January 2010

N 13 J 2009

State Station 11 Jan

12 Jan

13 Jan

14 Jan

15 Jan

16 Jan

17 Jan

18 Jan

19Jan

20Jan

21Jan

Sarawak Kuching 0.2 38.0 190.0

128.0

50.0 11.0 60.0 102.0

0.2 1.0 0.0

Sri Aman

0.0 0.0 21.0 6.0 5.0 5.0 21.0 6.0 0.4 25.0

0.0

Kapit 5.0 T 25.0 29.0 18.0 0.4 26.0 6.0 T 0.0 0.0Sibu 6.0 60.0 55.0 27.0 9.0 2.0 1.0 19.0 0.0 0.0 1.0Bintulu 0.0 0.2 176.

083.0 0.6 48.0 5.0 39.0 0.0 0.0 0.0

Nanyang, 13 January 2009

Rainfall in mm----- --------------

8 Jan 9 Jan 10 Jan 11 Jan 12 Jan

0Miri 0.0 2.0 48.0 95.0 39.0 T 7.0 2.0 0.0 0.0 0.4Limbang 1.0 17.0 32.0 49.0 14.0 1.0 7.0 1.0 0.0 0.0 0.0

0.3 13.0 48.0 227.0

27.0 1.0 20.0 0.4 T 0.0 0.0

0.6 23.0 7.0 32.0 101.0

6.0 34.0 2.0 T 0.0 0.0

KUCHING 107 102 187 129 5 SRI AMANI 11 58 86 47 0KAPIT 17 3 10 1 13SIBU 8 3 142 45 23

Kinabalu 0.6 56.0 2.0 15.0 66.0 11.0 0.0 15.0 0.0 0.0 1.0Kudat 0.0 0.4 14.0 19.0 10.0 34.0 37.0 24.0 2.0 5.0 0.0

19.0

3.0 34.0 3.0 17.0 114.0

31.0 0.0 18.0

0.0 0.0

Tawau 1.0 0.0 7.0 48.0 14.0 0.2 8.0 14.0 29.0

0.0 0.0

InteractionswithTopography,WRFStudy

Orography of South East Asia

CaseStudyoftheBorneoVortexth1120th Jan2010.

Intensive Observational Someresults.

IntensiveObservationalStudiesinNorthofBorneo.

Figure 9: Vertical time cross section of wind (kts) and relative humidity. Westerly component winds are plotted in blue. Regions with relative humidities in excess of 80% are shaded in red and below 20% in blue. [Source: station sonde data. Some are missing.]

Figure 10a: Vertical profiles of 4-hourly wind vectorsand magnitudes (contours knots) at Kuching fromand magnitudes (contours, knots) at Kuching from(top) 00 UTC 13 January 00 UTC and (bottom) 04UTC 16 January 04 UTC .

V in knots

U knots

RH

Figure 10b: Vertical profiles of (top) meridional winds [in knots, with northerlies

Case Study of the BorneoCaseStudyoftheBorneoVortex7th15th Jan2009

Formation of low level vortexFormationoflowlevelvortex

ObservationalStudiesBorneoVortexinKuching.-500

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GMS Enhanced IR Imageries on 7 January 2009

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The Impact of the ConvectionTheImpactoftheConvectionassociatedwiththeBorneoVortexonGlobalCirculation.

Figure 7a: Averaged 200 hPa velocity potential (contours, 106 m2 s-1 ) and divergent winds (vectors, ms-1 ) ) for the periods (top) 6 10 January 2010; (center) 11 15 January 2010; and (bottom) 16 20 January 2010.

Figure 7b: Averaged 200 hPa streamfunction (contours, 106 m2 s-1 ) and rotational winds (vectors, ms-1 ) ) for theperiods (top) 6 10 January 2010; (center) 11 15 January 2010; and (bottom) 16 20 January 2010.

Figure 7c: Hadley Circulation (m/s, averaged between 1100 E and 117.50 E) for the periods (top) 6 10 January 2010; (center) 11 15 January 2010; and (bottom) 16 20 January 2010.

Figure 7d: Walker-type Circulation (m/s, averaged between 00 N and 100 N) for the periods (top) 6 10 January2010; (center) 11 15 January 2010; and (bottom) 16 20 January 2010.

ComparisonbetweenNCEPandECWMF

Figure 1a: Averaged 200 hPa streamfunction (contours, 106 m2 s-1 ) and rotational winds(vectors, ms-1 ) ) for the periods (top) 6 10 January 2010; (center) 11 15 January 2010;and (bottom) 16 20 January 2010.

Figure 2a: Hadley Circulation (m/s) and relative humidity (%) averaged between 1100 E and 117.50 E) forthe periods (top) 6 10 January 2010; (center) 11 15 January 2010; and (bottom) 16 20 January2010.

Figure 2b: Walker-type Circulation (m/s) and relative humidity (%) averaged between 00 N and 100 N) for theperiods (top) 6 10 January 2010; (center) 11 15 January 2010; and (bottom) 16 20 January 2010.

Conclusion.1 This talk showed that the initiation of cold surge from the Siberian High is due to1. This talk showed that the initiation of cold surge from the Siberian High is due to

the push factor i.e. increase of pressure gradient and southward troughing of the Siberian High which is influence by the subtropical jet.

2. The cold surge is channelled by the topography of land and sea towards the South China Sea (SCS)South China Sea (SCS)

3. The surge increase the wind velocity over the SCS and the dry subsiding air start to become very moist due to evaporation from the warm sea surface.

4. The pull factor constitute the monsoon trough or ITZC that is now near Borneo islandisland.

5. The alignment of the Borneo island and Sumatra/Peninsular and its position across the equator contributed to the formation of a cyclonic vortex known as the Borneo Vortex. There is also a circum-island circulation that contribute to a zone of convergence associated with the Borneo Vortex and a zone of divergence nearof convergence associated with the Borneo Vortex and a zone of divergence near Tawau where a zone of low level diffluence was observed.

6. This cyclonic vortex ordered the process of deep convection and feed the moist air into the system to sustain rainfall for more than 48 hours.

7 There is also a diurnal influence of the spatial location of convection as observed7. There is also a diurnal influence of the spatial location of convection as observed earlier by Houze et al.

8. The deep convection of the Borneo vortex was observed to strengthen the ascending branch of the Hadley Circulation in both Hemisphere and also the E t W t W lk i l tiEast-West Walker circulation.

9. Via the Hadley Circulation the Borneo Vortex will then feedback into the subtropical jetstream hence completing the cycle.