WEATHER ANALYSIS OF EXTREME FOREST FIRE ON ISLAND BRAČ FROM 14
TO 17 JULY 2011
Boris Mifka
Višnja VučetićMeteorological and Hydrological Service
Maja Telišman PrtenjakGeophysical Departement "Andrija Mohorovičić" of the
Faculty of Science, University of Zagreb
Bihać, 28 April 2014
Photo: Siniša Miličić 14.7.2011 14:57
• WILDLAND FIRE POTENTIAL DANGER IN LONG LASTING DRY AND HOT PERIODS
• EXTREME FOREST FIRE BEHAVIORHIGH SPEED OF FIRE SPREAD, OCCURENCE OF MULTIPLE FIRE FRONTS
• OBJECTIVE TO ANALYZE WEATHER CONDITIONS DURING WILDLAND FIRE AT THE ISLAND BRAČ FROM 14 TO 17 JULY 2011
TO EXPLAIN DYNAMIC ATMOSPHERIC PROCESSES WHICH INFLUENCED EXTREME WILDLAND FIRE BEHAVIOUR
• AREA LOST IN FIRE WAS ABOUT 5600 ha (average annual burnt area is about 9000 ha )
INTRODUCTION
(Photo by:Siniša Miličić http://https://plus.google.com/110700915204596022370/posts/85atoEBhe5K (Photos by:Predrag Mandić i Pero Dragičević, http://www.braconline.com.hr)
Split-Marjan
Zadar-airport
Hvar JelsaBol
SutivanBol-airport
Synoptic and automatic stationsClimatological stationsRadio-sounding stationAutomatic station
Zagreb
DATA
METEOROLOGICAL ELEMENTS:WIND SPEED AND DIRECTION,RELATIVE HUMIDITY, AIR TEMPERATURE AND PRESSUREMETEOROLOGICAL STATIONS AND DATA:10-min DATA FROM AUTOMATIC STATIONS HOURLY DATA FROM SYNOPTIC STATIONSDATA AT 7,14 I 21 H CET FROM CLIMATOLOGICAL STATIONS RADIO-SOUNDING DATA AND VERTICAL PROFILES
PrecipitationRelative humidityWind speedAir temperature
PrecipitationRelative humidityAir temperature
PrecipitationAir temperature
FFMC DMC DC
Wind speed ISI BUI
FWI
CANADIAN FWI METHOD
RESULTS FWI METHOD
• MID-ADRIATIC, JUNE AND JULY 2011 DRY AND HOT WEATHER
1 21 42 63 84 105 126 147 168 189 210 231 252 2730
20
40
60
80
100
120SPLIT-MARJAN, 1.1-30.9.2011.
dani
FF
MC
,IS
I,F
WI
FFMC ISI FWI
DIURNAL CYCLES OF WIND SPEED AND DIRECTION
wind speed (m
/s)w
ind speed (m/s)
win
d di
rect
ion
( °)
win
d di
rect
ion
( °)
FIRE STARTFIRE START
FIRE STARTFIRE START
CETCET
CETCET
Datum
Tmaks (°C)
Tmin (°C)
Tsred (°C)
RVsred (%)
RV14 (%)
14.7.2011. 35.0 27.0 31.5 35 38 15.7. 2011. 32.0 25.2 27.6 61 58 16.7. 2011. 31.8 22.7 27.8 59 50 B
OL
17.7. 2011. 30.6 22.2 26.4 40 42 14.7. 2011. 36.2 25.2 30.6 64 59 15.7. 2011. 34.1 20.2 29.1 60 63 16.7.2011. 35.0 19.7 29.6 55 57
SU
TIV
AN
17.7.2011. 32.5 19.7 28.8 57 55
AIR TEMPERATURE AND REL. HUMIDITY
AIR PRESSURE
DIURNAL CYCLES
FIRE STARTFIRE START
FIRE STARTFIRE START
air
te
mp
era
ture
( °
C)
a
ir t
em
pe
ratu
re (
°C
)
CETCET
CETCET
r
ela
tive
hu
mid
ity (
%)
r
ela
tive
hu
mid
ity (
%)
air
pre
ssu
re (
hP
a)
air
pre
ssu
re (
hP
a)
DATEDATE
SURFACE METEOROLOGICAL FIELDS SIMULATIONS OF ALADIN/HR MODEL
14. 7.2011. – WEAK ANTICYCLONE ON MESOSCALE (MA) OVER BOSNIA, SHALLOW CYCLONE OVER ADRIATIC SEA ( 1010 hPa ISOBARE IS OVER BRAČ AND HVAR)
• Vmaks 8–10.8 m/s NEAR BRAČ
BOTTOM SIDE OF MA : SE SE–E WIND INCOMING DRY AND HOT AIR FROM THE DALMATIAN HINTERLAND (RH < 40 % & Tmaks = 35 °C)
14.7.2011. WIND
RELATIVE HUMIDITY AIR PRESSURE
0 2 4 6 8 10 12 14 16 180.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0ZADAR-A SONDAŽA 14-17.7.2011.
brzina vjetra (m/s)
vis
ina (
km
)
14.7. 00 UTC
14.7. 12 UTC
15.7. 00 UTC
15.7. 12 UTC
16.7. 00 UTC
16.7. 12 UTC
17.7. 00 UTC
17.7. 12 UTC
0 90 180 270 3600.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
smjer vjetra ( °)
vis
ina (
km
)
ZADAR-AIRPORT 14–17 July 2011.00 and 12 UTC
-INVERSION TOP 994 m
-LOW LEVEL JET 12. 9 m/s at 379 m
-INVERSION TOP 994 m
-LOW LEVEL JET 12. 9 m/s at 379 m
0 2 4 6 8 10 12 14 16 180.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0vis
ina (
km
)
brzina vjetra (m/s)
BOL 14 .7.2011 ALADIN/HR
8 UTC
9 UTC
10 UTC
11 UTC
12 UTC
13 UTC
14 UTC
15 UTC
0 90 180 270 3600.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
smjer vjetra ( °)
BOL ALADIN:14 July 2011. 8-15 UTC
WIND SPEED MAX <12m/sWIND SPEED MAX <12m/s
(source: http://satreponline.org)
VERTICAL CROSSECTIONS, 14 July 2011 at 12 UTC
WARM ADVECTION BUOYANCY SPEED
• LOADED GUN THEROY – TEMPERATURE INVERSION AS A CAP ON A STEAM POT
• CIN = -417.83 J/kg AT ZADAR-A & CAPE 463.01 J/kg
• MECHANISM OF CONVECTION TRIGGERING – VISINSKA CIKLONA CUT OFF, WITH CONVECTIVE CLOUDINESS AT WATER WAPOR SATELITE IMAGES
THOUGH IT WAS TO DRY FOR CONVECTIVE CLOUDINESS
DEVELOPEMENT
• VCS INCREASED VERTICAL SPEED VERTICAL SPEED (-2 DO -4 hPa/h 0.5–1 cm/s od 950–700 hPa) 14 to15 July 2011 Max. at 700 hPa
WARM ADVECTION TEMPERATURE INVERSION?
CONCLUSION
• GREAT AREA AFFECTED BY FIRE (ROUND 5200 ha)
• DRY AND HOT CONDITIONS BEFORE THE FIRE START HIGH FWI INDEX
• MODERATE TO STRONG SE WIND PRECEDED THE FIRE START
• MESOSCALE: SHALOW CYCLONE ABOVE ADRIATIC SEA AND WEAK ANTIYCYCLONE OVER BOSNIA DURING THE PASAGE OF DRY FRONT
• SOUNDINGS STABILE LAYER AT 994 m, LOW LEVEL JET BELOW, INCOMING COLD FRONT EXTREME WILDLAND FIRE BEHAVIOUR
• IMPACT OF THE WARM ADVECTION ON STABILE LAYER – DISTORTION (LOADED GUN THERY) ?
• IN THE MORNING OF 15 July 2011, WEATHER CHANGE ETESIA WINDS+SEA BREZE MAESTRAL
ALADIN/HR• HYDROSTATIC MODEL WITH 8 KM HORIZONTAL RESOLUTION AND 37
VERTICAL LEVELS (LOWEST AT 17 M)
• SPECTRAL MODEL WITH TERAIN FOLOWING VERTICAL COORDINATE
• PRIMITIVE EQUATION SYSTEM AND PHYSICAL PARAMETRIZATION INCLUDED
OPERATIVE MODE INITIAL AND BOUNDARY CONDITIONS (APPROVED BY RCLACE DATA ASSIMILATION CYCLE - ARPEGE (Meteo France) )
DYNAMICAL ADAPTATION downscaling from 8 km to 2 km resolution on a 450 X 450 point grid
PRILOG 1
14.7.2011 U 12 UTC USPOREDBA
RADIOSONDAŽNIH MJERENJA I PROCJENE
MODELA ALADIN/HR
14.7.2011 U 12 UTC USPOREDBA
RADIOSONDAŽNIH MJERENJA I PROCJENE
MODELA ALADIN/HR
PRILOG 2
Prognostički vertikalni vremenski presjek atmosfere za Bol od 14. do 16. srpnja 2011. prema modelu ALADIN/HR.
VERTIKLANA STRUKTURA ATMOSFERE I USPOREDBA S NUMERIČKIM SIMULACIJAMA
• U POČETKU ŠUMSKOG POŽARA OKO 2000 ha IZGORENOG RASLINJA U VREMENU OD 2 SATA NAKON POČETKA, UZ POPRATNE ZANIMLJIVE METEOROLOŠKE POJAVE
• MET- VELIČINE IZ RADIOSOANDAŽE I PSEUDOTEMPOVI (ALADIN/HR): BRZINA I SMJER VJETRA, TEMPERATURA I POT. TEMPERATURA ZRAKA I UZGONSKA FREKVENCIJA
SONDAZA:• VJETAR : 14.7.2011. U 12 UTC MAKS. BRZINA OD 12.9 m/s NA
379 m MLAZNA STRUJA PREMA 1. KRITERIJU
(BLACKADAR, 1957), IDUĆEG DANA SLABI SMJER VJETRA ZAKREĆE IZ SE U S I SW (1512
m )
• TEMPERATURNA INVERZIJA - OD 955-994 m NAD TLOM UZ OPADANJE TEMPERATURE U TOM SLOJU 3.6 °C/100 m
• PSEUDOTEMP: – MODELIRANE PROCJENE VISINSKIH PROFILA POMOĆU MODELA ALADIN