Environmental

Communication

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

ABSTRACT

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.

KEY WORDS: CLIMATE CHANGE, LARSE-WG, KHAZAR BASIN, PRECIPITATION, TEMPERATURE

372

ARTICLE INFORMATION:

*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

Thomson Reuters ISI ESC and Crossref Indexed Journal

NAAS Journal Score 2017: 4.31 Cosmos IF: 4.006

reserved.

Online Contents Available at: http//www.bbrc.in/

DOI: 10.21786/bbrc/10.3/6

INTRODUCTION

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

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS EXPLORING CLIMATE CHANGE OVER KHAZAR BASIN 373

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.

MATERIAL AND METHODS

STUDY REGION

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

374 EXPLORING CLIMATE CHANGE OVER KHAZAR BASIN BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

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).

MATERIALS AND METHODS

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.

RESULTS AND DISCUSSION

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

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS EXPLORING CLIMATE CHANGE OVER KHAZAR BASIN 375

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

376 EXPLORING CLIMATE CHANGE OVER KHAZAR BASIN BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

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

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS EXPLORING CLIMATE CHANGE OVER KHAZAR BASIN 377

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

378 EXPLORING CLIMATE CHANGE OVER KHAZAR BASIN BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

FIGURE 11. Map of difference of precipitation (future-base)

Table 1. Change of the observed and simulated climatic variables across the Basin.

Min temperature

(ºC)

Max temperature

(ºC)

Precipitation

(mm)

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

CONCLUSION

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-

erably.

FUNDING

This study has been funded by Payam-e Noor University.

CONFLICT OF INTERESTS

None declared

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