BIOMETEOROLOGICAL POTENTIAL OF
CROATIAN ADRIATIC COAST
Ksenija Zaninović
Meteorological and hydrological service of Croatia
HR-10000 Zagreb, Grič 3
E-mail: Ksenija.Zaninovic@cirus.dhz.hr
Abstract
The article deals with the analysis of biometeorological conditions in the period 1979-1998 at 8
meteorological stations along the Croatian Adriatic coast: Rovinj (Istra Peninsula), Crikvenica
(Kvarner Bay), Šibenik (middle Adriatic coast) and Dubrovnik (southern Adriatic coast) at the
coast, as well as at the islands Rab, Vela Sestrica, Hvar and Palagruža. The most comfortable
periods at the Adriatic coast are April and May as well as September and October. During the
hottest summer months July and August it is warm in the morning and evening and hot in the
afternoon. Due to the cooling effect of the sea and the wind, the excess heat episodes are rare and
they happen mostly only in the afternoon. From the late autumn until the early sprig, the
biometeorological conditions are ideal for the sport activities.
Key words: thermal sensation, TWH index
Introduction
The information about biometeorological conditions, as the complex influence of several
meteorological parameters on thermal sensation of man, has the great importance in tourism. In
combination with some other meteorological parameters, such as air and sea temperature, sunshine
duration, amounts and number of days with precipitation and wind roses can be presented
graphically like posters to tourists. It enables everyone to choose the most convenient period for
holidays, depending on personal conditions and needs. For example, elder and deceased people,
who difficulty bear summer heat, could choose the period of pleasant biometeorological conditions,
which prevail at the Adriatic coast during spring and autumn, to take vacation with slow walks. For
sportsmen, who prefer an active vacation, pleasant or even cool conditions would be more
convenient than summer heat, when the organism has to spend energy for defence from heat.
Data and method
In the first part of the article the climatological and bioclimatological prospect, based at the analysis
of 10-day periods of meteorological parameters, important for the tourism and recreation is
presented.
In the second part the biometeorological conditions in the period 1979-1998 at eight meteorological
stations along the Croatian Adriatic coast are analysed. These are Rovinj at Istra Peninsula,
Crikvenica situated in Kvarner Bay, Šibenik at middle and Dubrovnik at southern Adriatic coast, as
well as at the islands Rab, Vela Sestrica (National park Kornati islands), Hvar and Palagruža. The
biometeorological conditions are analysed by means of the ten-day mean values of thermal
sensation at 7am, 2pm and 9pm, and by means of the probability of occurrence of different thermal
sensation. The thermal sensation is defined by means of TWH index (temperature-wind speedhumidity), (Zaninović, 1992; Zaninović, 1994).
The prospect of climate and bioclimate
The climatological and biometeorological prospect contains the analysis of thermal, aesthetic and
physical parameters important for the tourists. The analysis is performed for 10-day periods, as a
better information for the tourists, which usually spend a week or two on holidays rather than a
month. So the tourists can be inform about the weather they can expect during their holidays.
The bioclimatic prospect of Hvar is presented at the Figure 1. The thermal parameters are presented
at the three pictures on the left. The first one presents mean, mean minimum and mean maximum
temperatures. The annual courses of the number of days with different temperature characteristics
are below: warm (tmax25ºC) and tropical days (tmax30ºC) and days with warm nights (tmin20ºC),
and cold (tmin<0ºC), ice days ((tmax<0ºC) and days with tmin-10ºC (those two don’t appear in Hvar).
In the middle column the aesthetic and physical characteristics of climate are presented. From the
aesthetic parameters clear and cloudy days (the picture at the top) and insolation and cloudiness
(middle picture) are analysed. The annual courses of physical parameters: precipitation and number
of days with precipitation are at the bottom. The analysis of biometeorological conditions is
presented by means of thermal comfort distribution during the year as well as the probability of
occurrence of different thermal sensations. Finally, there is the annual wind rose for all terms
together. Sometimes, for example especially for the sailors, the roses for seasons and different terms
of observations can be presented separately.
HVAR – CLIMATE AND BIOCLIMATE, 1961-1990.
Figure 1.
10
35
Clear days
90
70
15
0
1 I3
30
7
Annual course of clear and
cloudy days
20
Summer days (tmax>25oC)
18
Tropical days (tmax>30oC)
Warm nights (tmin>20oC)
16
Cloudiness
12
6
10
8
4
6
4
40%
40
20%
20
2
2
1
I
3
II
5
0%
0
0
III
IV
V VI VII
X
XI
XII
VIII IX
7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
I
3
1
Annual course of warm and tropical days
and days with warm nights
II
III
IV
V VI VII VIII IX
X XI
XII
5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
0
1
0
I
Annual course of insolation and
cloudiness
II
III
IV
V
VI
100
8
10
Precipitation
Days
4
8
60
6
40
4
20
2
WNW
2
0
1I
3
II5
7 III9
11
17 19
23 25IX27 29
35
IV 13V 15 VI
VII 21 VIII
X 31XI 33 XII
Annual course of cold days
1
I
3
II
5
7
III
IV
V VI
VII VIII IX
X XI
XII
9 11 13 15 17 19 21 23 25 27 29 31 33 35
Annual course of precipitation
and rainy days
XI
XII
21
14
7
ENE
-50.9
E
WSW
ESE
SW
SSW
SE
SSE
S
0
X
LEGEND
NNE
NE
15
5
W
Days
Precipitation (mm)
80
6
NNW
NW
Rainy days
Cold days (tmin<0oC)
IX
Probability for different thermal comfort
N
10
VII VIII
34
2
60%
60
31
4
14
28
Days
6
80%
80
8
Cloudiness (tenths)
Insolation (hours)
8
100%
100
10
Insolation
25
10
Distribution of thermal comfort during day and year and
22
Annual course of the air and see temperatures
relative humidity (10-day periods)
IV 13 V15 17
VI 19VII
VIII 25IX27 29
X 31XI33 XII
5II 7 III9 11
21 23
35
19
III
IV V
VI VII
VIII IX
X XI
XII
7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
16
3
II
5
13
1
I
2
10
0
50
14
7
Relative humidity
Mean min. temperature
Mean temperature
Mean max. temperature
Sea temperature
5
4
4
10
6
Probability (%)
20
21
Cloudy days
8
Days
25
Relative humidity (%)
Temperature (oC)
30
0
Annual wind rose
extremely cold
very cold
cold
cool
comfortable
warm
hot
very hot
extremely hot
Bioclimatic conditions along the Adriatic coast
The bioclimatic conditions along the Adriatic coast are analysed by means of the thermal
comfort distributions during the year and the probabilities of occurrence of different thermal
sensations at eight meteorological stations: Rovinj (Istra Peninsula), Crikvenica (Kvarner
Bay), Šibenik (middle Adriatic coast) and Dubrovnik (southern Adriatic coast) at the coast, as
well as at the islands Rab, Vela Sestrica (Kornati islands), Hvar and Palagruža (fig. 2).
CRIKVENICA
ROVINJ
RAB
VELA SESTRICA
ŠIBENIK
HVAR
DUBROVNIK
PALAGRUŽA
Figure 2. The position of analysed stations.
The Croatian Adriatic coast has different biometeorological conditions although is relatively
small area. Generally, the period of the prevailing cold thermal sensation lasts from the
December until March, but mornings and evenings are cold earlier (in November), while in
spring at the most stations cool afternoons begin to occur already at the beginning of March
(Figure 3). However, at some locations (Šibenik and Palagruža) the prevailing cold sensation
occurs already in November, mainly due to strong winds rather than low temperatures. On the
other hand, the cold period at some station is rather shorter. In December in Crikvenica, Vela
Sestrica at Kornati islands and in Hvar only mornings and evenings are cold, while the
afternoons are partly cold only in January and February. April in spring and October and
somewhere November in autumn are cool. At Palagruža, the island isolated in the middle of
the Adriatic sea, the period of cold sensation lasts until the end of April, while May is cool.
The most pleasant period with prevailing sensation of comfortable occurs in May and June as
well as in September and in the first part of October. During summer warm is prevailing,
while hot occurs only during the hottest part of the day, mainly from the middle of July until
the middle of August. Only at the island Palagruža the sensation very warm occurs on average
only in the first 10-day period in August. On the other hand, the sensation of very hot on the
average occurs only at Vela Sestrica at the end of July and at the beginning of August.
The analysis of the probability of occurrence of different thermal sensation gives more detail
information about bioclimate. On the Figure 4 the probabilities of occurrence of days with
different thermal sensations according to the mean daily values are presented. Although they
don’t appear in the average values, the sensations of extremely and very cold appear during the
winter. The most frequently they appear in Šibenik and Palagruža, usually connected with
strong winds. For example, in Šibenik in January and February even up to 20% of extremely
cold sensation mainly as the effect of well-known bora wind appears. On the other hand,
during the winter months, when it is cold on average, one can expect even 20 to 40% of cool
days according to the mean daily values of thermal sensation. During the summer, the mean
daily sensation very hot appears relatively rarely, even at Vela Sestrica where in July and
August mean afternoon values of thermal comfort are in the class very hot.
Choosing the period in which the tourist wants to spend the holidays, he can get quite s
precise information about the thermal sensation that he can expect in that period.
Conclusions
The analysis of climate and bioclimate, especially if is presented at clear and simple
way that everyone can understand it, gives a basis for promotion of natural possibilities of
tourist destinations. The tourist managers can use the meteorological knowledge in
propaganda and offer wide spectra of possibilities for spending holidays, from the summer
tourism with sun and sea bathing, but also for health, recreation or sport purposes, depending
on climate and bioclimate conditions during the pother parts of the year. Also, physicians
should warn their patients what periods are inconvenient for them and suggest the best period
for improving their health.
References
Zaninović, K., 1992: Limits of Warm and Cold Bioclimatic Stress in Different Climatic
Regions. Theor. Appl. Climatol., 45, 65-70.
Zaninović, K., 1994: Fizikalna osnova za bioklimatsku klasifikaciju Hrvatske, Magistarski
rad, Sveučilište u Zagrebu, Poslijediplomski studij prirodnih znanosti, Fizika atmosfere,
Zagreb, 80 str.
de Freitas, C. R., 1990: Recreation climate assessment. International Journal of Climatology,
10, 89-103.
Rovinj
Rab
21
21
14
7
14
I
I
II
III
IV
V
VI
VII
VIII
IX
X
XII
XI
7
I
I
II
III
IV
V
Crikvenica
14
I
IX
X
XI
XII
I
II
III
IV
V
VI
VII
VIII
IX
X
XII
XI
7
VII
VIII
IX
X
XI
XII
VII
VIII
IX
X
XI
XII
VIII
IX
X
XI
XII
I
I
II
III
IV
V
Sibenik
VI
Hvar
21
21
14
14
I
I
II
III
IV
V
VI
VII
VIII
IX
X
XII
XI
7
I
I
II
III
IV
V
Dubrovnik
VI
Palagruza
21
21
14
7
VIII
21
14
7
VII
Vels Sestrica
21
7
VI
14
I
I
II
III
IV
V
VI
VII
VIII
IX
X
XII
XI
7
I
I
II
IV
V
VI
VII
21
14
7
extremely cold
very cold
cold
cool
comfortable
warm
hot
very hot
extremely hot
Figure 3. The thermal sensation according to TWH-index during day and year along the
Croatian Adratic coast, period 1979-1998.
Rovinj
Rab
100%
100
100%
100
90%
80
80%
Probability (%)
Probability (%)
80
80%
60
60%
40%
40
70%
60
60%
50%
40%
40
30%
20%
20%
20
20
10%
0%
0
35
XI
33
X
31
29
IX
27
VIII
25
23
VII
21
VI
19
17
V
15
IV
13
9
III
11
II
7
5
I
3
1
0%
0
XII
1I
Crikvenica
100%
100
7III 9 IV
11 13V 15 VI17 19
23 25IX 27 X
29 31XI 33 XII
35
VII 21VIII
Vela Sestrica
100%
100
80
80%
80
80%
Probability (%)
Probability (%)
3 II5
60
60%
40%
40
60
60%
40%
40
20%
20%
20
20
0%
0
0%
0
1I
3 II5
7III 9 IV
11 13V 15 VI
17 19
23 25IX 27 29
35
VII 21 VIII
X 31XI 33 XII
1 I 3 II5
7III 9 IV
11 13V 15 VI17 19
23 25IX27 29
35
VII21VIII
X 31XI 33 XII
Šibenik
100%
100
Hvar
100%
100
80%
80
Probability (%)
60
60%
40%
40
60%
60
40%
40
Dubrovnik
100%
100
X
XI
34
IX
31
VI VII VIII
28
V
25
IV
22
III
19
II
XII
Palagruža
100%
100
80
80%
Probability (%)
80
80%
Probability (%)
I
16
7III 9 IV
11 13V 15 VI17 19
23 25IX 27 X
29 31XI 33 XII
35
VII 21VIII
13
3 II5
10
1I
7
0%
0
0%
0
4
20%
20
20%
20
1
Probability (%)
80
80%
60
60%
40%
40
20%
60
60%
40%
40
20%
20
20
0%
0
0%
0
1I
3 II5
7III 9 IV
11 13V 15 VI17 19
23 25IX 27 29
35
VII 21VIII
X 31XI 33 XII
1I
3 II5
7III 9 IV
11 13V 15 VI17 19
23 25IX 27 29
35
VII 21VIII
X 31XI 33 XII
Figure 4. The probability of occurrence of different thermal sensation according to TWH
index along the Croatian Adriatic coast, period: 1979-1998.