Biosci. Biotech. Res. Comm. 10(3): 372-379 (2017)
Exploring climate change over Khazar Basin based on
LARSE-WG weather generator
Amir Hossein Halabian
and M.S. Keikhosravi
Associate Professor, Department of Geography, Payam-e Noor University, Tehran, Iran
Invited Teacher, Payam-e Noor University, Tehran Iran
The aim of this paper is to analyze climate change over Khazar Basin for the next decades. Khazar Basin is considered
as one the most important one in Iran due to its speci c climatic conditions. The experiment of climate change across
the basin was conducted using 21 synoptic stations by the application of LARS-WG weather generator, the years from
1992 to 2015 were selected as the base period and the analyses were carried out to estimate climate change over the
2046-2065. The analyses for future climate change then were compared to the base period. The results revealed that
in the future period, on average precipitation will decrease -37.1 mm and min and max temperature will increase
3.8 and 3.2 ºC respectively compared to the base period. Therefore it could be deduced that climate change can have
adverse effects on the Basin and some adaptive steps must be taken to reduce the bad effects accordingly.
*Corresponding Author: halabian_a@yahoo.com
Received 27
Nov, 2017
Accepted after revision 26
Sep, 2017
BBRC Print ISSN: 0974-6455
Online ISSN: 2321-4007 CODEN: USA BBRCBA
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© A Society of Science and Nature Publication, 2017. All rights
Online Contents Available at: http//www.bbrc.in/
DOI: 10.21786/bbrc/10.3/6
Developing countries are vulnerable to climate changes,
mainly due to their limited adaptive capacities in deal-
ing with extreme events (Pouliotte etal., 2009). the main
ndings from the latest report on climate change and a
special report on extreme events from the Intergovern-
mental Panel on Climate Change show a greater consen-
sus about a likely increase in the frequency and intensity
of heavy precipitation events over land areas since 1950
(IPCC). Therefore, it is of great importance to predict cli-
mate change for the future decades to deal with its pos-
sible effects over different geographical territories. In the
past years many investigations have been conducted to
reveal climate change for different temporal resolutions
and also for different parts of the globe. The effects of
climate change has been simulated in 12 rivers of India,
the authors have concluded that under a scenario of cli-
mate change a general reduction in the quantity of the
available runoff will occur and the intensity of  oods
Amir Hossein Halabian and M.S. Keikhosravi
in various parts of India may get deteriorated (Gosain
etal., 2006). The results of an investigation also show
that between 1995 and 2025, the extents of the regions
that will be affected by severe water stress will increase
and this condition is especially true for Southern and
Western Africa and South Asia (Alcamo et al., 2000).
In a research it was found that based on ENSEMBLES
anthropogenic climate-change (ACC) global simulations
and the Climate version of the Local Model (CLM) pre-
cipitation is expected to be critically decreased in three
selected region of Greece (Paparrizos etal. 2016).
In another study it was revealed that over the Central
Asian region, the aridity is expected to increase (Lioubimt-
seva and Henebry, 2009). In another research work it was
found that for the periods from 2010 to 2040 and 2070 to
2100 and based on the CGCM 3.1 dry regions of the Iran will
get less precipitation (Abbaspour etal., 2009). The  ndings
of Arnell and Gosling (2016) revealed that under the climate
model (HadCM3 and SRES A1b), in 2050 the current 100-
year  ood would occur at least twice as frequently across 40
% of the globe, approximately 450 million  ood-prone peo-
ple and 430 thousand km2 of  ood-prone cropland would
be exposed to a doubling of  ood frequency, and global
ood risk would increase by approximately 187 % over the
risk in 2050 in the absence of climate change.
Zhang et al. (2016) estimated stream  ows in the
Xin River Basin, China based on climate change sce-
narios downscaled from different GCMs (BCC-CSM1.1,
CanESM2, and NorESM1-M) under three Representative
Concentration Pathways (RCPs). The ensemble average
of stream ow in GCMs demonstrated that many RCPs
signi cantly decrease from May to June but increase
from August to September relative to the baseline period.
The goal of this investigation is to reveal the changes of
temperature and precipitation over the study region. As
rain fed agriculture is very common in the basin the
ndings of the current paper could assist policy makers
to have a better picture of climate of the study region for
the next decades.
Khazar Basin is geographically located in the north parts
of Iran with a very diverse climate. The Alborze Moun-
tains which are extended from west to east have created
two distinct climates in the region. The north parts of
the Basin receive a lot of precipitation throughout the
year while the southern counterpart receives much less
precipitation as the humidity is often con ned to the
northern areas of the Basin. The climate of the north part
is mild and humid but the western parts of the region
FIGURE 1. General location of Khazar Basin.
Amir Hossein Halabian and M.S. Keikhosravi
FIGURE 2. Location of the stations used in this study
have a cold climate. The general location of the Basin
has been depicted in Figure (1).
In this paper, the daily precipitation, min temperature
and max temperature data of 21 synoptic stations across
the Basin were applied from 1992 to 2015. The applied
stations are operated by Islamic Republic of Iran Meteor-
ological Organization (IRIMO) and are presented in text
les by the IRIMO. In order to ensure a valid climate
change analyses it is important to examine the accuracy
of the applied data, so the climate variables of all the sta-
tions have been checked for any possible outliers in the
time series. Despite the fact that the resolution of Gen-
eral Circulation Models (GCMs) has been signi cantly
increased but they still cannot predict meteorological
outputs for small scales. Therefore, some models have
been created to downscale the GCMs output. LARS – WG
is a model which is used to downscale the GCMs output.
In this investigation the LARS – WG version 5.5 was
utilized. This version includes different GCMs data and
the BCM2 which is one the GCMs has also been included
in the model. LARS – WG utilize separate semi-empirical
distributions for each of variables including min, max
temperatures and precipitation and this downscaling
method has been used in several studies (Semenov etal.,
1998; Qian etal., 2004; Babaeian and Kwon, 2005; Law-
less and Semenov, 2005; Khan etal., 2006).
In the next step to prepare the data to run the model,
the data of each station were transferred into the format
of the LARS- WG weather generator. The observed daily
max temperature, min temperature and precipitation
series for 1992–2015 at 21 stations are used as inputs to
the LARS- WG weather generator and then the weather
series of the variables are generated for each site. Using
the BCM2 general circulation model with emission sce-
nario of SRA1B we simulated the climate variables of
max temperature, min temperature and precipitation for
the future period of 2046-2065 over the Basin. Then we
computed the Basin wide average of min, max and pre-
cipitation for the observed period and also for the future
period based on the obtained results from the model.
Using the Surfer 12 software package, all the three cli-
mate variables were then interpolated over the Basin
and mapped.
The calculated observed min temperature for the Basin
indicates that the central parts of the Basin are the warm-
est areas compared to the other regions and in some
parts the annual temperature is nearly 13 ºC, the west
and east parts of the Basin are cold parts and in some
areas in the north-west the min temperature falls below
0 ºC (Figure 3). The simulated annual min temperature
indicates that compared to the based period there will
be increase in temperature (Figure 4) and in all areas of
the Basin min temperature will increase in various rates.
The highest rate of increase is seen over the north-west
parts of the Basin that are considered to be the cold
and mountainous regions (Figure 5). In these regions the
temperature increase is up to nearly 7 ºC but in central
areas the increased temperature is less evident and it is
generally less than 2 ºC.
For the observed period the max warmest tempera-
tures in the Basin are generally seen over central to the
east regions while the cooler max temperatures are over
north-west of the Basin. The max temperature is below
15 ºC in the coolest parts but in the warm areas, the
max temperature exceeds 21 ºC (Figure 6). In the future
period the max temperature will increase for entire of
the Basin (Figure 7) and the temperature in some areas
will exceed 24 ºC. The map of difference of max tem-
perature (future – base) indicates that north areas of the
Basin from north-west to north-east will experience the
Amir Hossein Halabian and M.S. Keikhosravi
FIGURE 3. Map of observed min temperature (ºC) for the based period (1992-2015).
FIGURE 5. Map of difference of min temperature (future-base)
FIGURE 4. Map of simulated min temperature (ºC) for the future period (2046-2065).
Amir Hossein Halabian and M.S. Keikhosravi
FIGURE 6. Map of observed max temperature (ºC) for the based period (1992-2015).
FIGURE 7. Map of simulated max temperature (ºC) for the future period (2046-2065).
FIGURE 8. Map of difference of max temperature (future-base)
Amir Hossein Halabian and M.S. Keikhosravi
FIGURE 9. Map of observed precipitationfor the based period (1992-2015).
FIGURE 10. Map of simulated precipitation (mm) for the future period (2046-2065).
highest rate of temperature increase, in these regions
the temperature can possibly increase up to 4.5 ºC but
this rate is far less evident in south-west of Basin, in
these areas temperature increase is below 2 ºC in general
(Figure 8). The overall rate of temperature increase for
the entire of the Basin is 3.2 ºC.
Owing to the complex topography of the Basin, the
amount of precipitation is also highly variable across the
Basin, in the central north parts, the annual precipitation
is very signi cant and it’s due to the proximity to Caspian
Sea. In some parts the annual precipitation exceeds 1300
mm on average (Figure 9). The map of simulated pre-
cipitation for the future period indicates that many areas
of the Basin will experience reduction in precipitation
(Figure 10). The rate of decrease is various from region to
region, the highest reduction is identi able over central to
the west parts with the average reduction of up to 140 mm
while some areas from central to the east have an increase
amount of precipitation compared to the base period with
an increase of up to 40 mm (Figure 11). In general for the
future period, the precipitation will decrease 37.1 mm in
comparison to the base period.
Amir Hossein Halabian and M.S. Keikhosravi
FIGURE 11. Map of difference of precipitation (future-base)
Table 1. Change of the observed and simulated climatic variables across the Basin.
Min temperature
Max temperature
Mean of observed (1992-2015) 5.4 17.2 555.5
Mean of simulated (2046-2065) 9.2 20.4 518.4
Difference (future – base ) 3.8 3.2 -37.1
In this investigation the climatic variables, including
min, max temperature and precipitation were applied
from 21 synoptic stations across the Khazar Basin and
were then downscaled using LARS- WG weather genera-
tor for the future period (2046-2065). The  ndings of
this study revealed that over the future period the min
and max temperature will increase across the Basin and
the rate of the increase is 3.8 and 3.2 ºC respectively. In
some parts of the Basin in the north-west, the rate of
increase for min temperature is up to 6.8 ºC while for
max temperature it is up to 4.5 ºC. The analyses also
showed that in general precipitation will decrease for
the future period with the average amount of 37.1 mm,
but there are some limited areas in the Basin which will
experience a little increase for the precipitation. From
the obtained results of this study it can be concluded
that the Basin will be highly affected by climate change
in the future which can have signi cant impacts on the
ecosystem. Therefore serious adaptive steps must be
taken to mitigate the adverse effects of climate change
because the agriculture in this Basin is mostly rain
fed and temperature increase along with precipitation
decrease can deteriorate the climatic conditions consid-
This study has been funded by Payam-e Noor University.
None declared
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