RADIATION PROGRAM AT TAMANRASSET

ALGERIA

RESULTS OF RADIATION MEASURE

SINCE 1994

By .O.BOUZIANE

Algeria Map

TAMANRASSET

Radiation instruments on the roof

MEASURE OF RADIATION

- SOLAR RADIATION ( 0.28 µm – 4 µm )

Measure of Downward flux Since September 1994

Direct , Global , Diffuse , RG8 (>=0.69 µm)

- ATMOSPHERIC RADIATION ( Long Wave ) : 4 µm -100 µm

Measure of Downward flux Since Mars 2000

Since this date , change in measure of diffuse : shade disk in place

of shadow band.

- Calibration of Instruments : PSP §NIP IN SITU WITH AHF REFERENCE N° 29225

THE TURBIDITY IS VERY LOW IN THE WINTER ( NOV-MARS ) AND VERY HIGH FROM APRIL TO SEPTEMBER : VERY HAZY

Measured since january 1995 with Sun photometer ( 500 nm)

Daily variation of turbidity

0

200

400

600

800

1000

1200

1400

1600

1800

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Date: 1/1/95 to 31/12/08

Tu

rbid

ity i

n 1

/1000

YEARLY VARIATION OF TURBIDITY AT TAMANRASSET

0

50

100

150

200

250

300

350

400

95 96 97 98 99 0 1 2 3 4 5 6 7 8

YEARS : 1995-2008

TUR

BID

ITY

(1/1

000)

THE YEARLY AVERAGE OF THE TURBIDITY CHANGE FROM 0.170 TO 0.340.

Measure OF RADIATION AT Tamanrasset

Daily Variation of Diffuse ( MJ)

0

2

4

6

8

10

12

14

16

18

20

1 366 731 1096 1461 1826 2191 2556 2921 3286 3651 4016 4381 4746 5111 5476

date :from 1/1/95 to 31/12/2009

Dif

fuse in

MJ

Daily variation of global ( MJ)

0

5

10

15

20

25

30

35

40

1 366 731 1096 1461 1826 2191 2556 2921 3286 3651 4016 4381 4746 5111 5476

date : from 1/1/95 to 31/12/2009

Glo

bal in

MJ

Daily variation of Direct (MJ)

0

5

10

15

20

25

30

35

40

45

50

1 366 731 1096 1461 1826 2191 2556 2921 3286 3651 4016 4381 4746 5111 5476

date : from 1/1/95 to 31/12/2009

Dir

ect

in M

J

Daily variation of PIR ( MJ)

10

15

20

25

30

35

40

1 366 731 1096 1461 1826 2191 2556 2921 3286

date : from 1/1/2001 to 31/12/2009

PIR

in

MJ

Monthly average diffus/global

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

1 2 3 4 5 6 7 8 9 10 11 12

Months

yearly ratio Diffus/Global

0.2

0.22

0.24

0.26

0.28

0.3

0.32

0.34

0.36

0.38

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Years : 1995-2009

Year Diffus/glb

1995 0.277

1996 0.248

1997 0.273

1998 0.293

1999 0.246

2000 0.306

2001 0.249

2002 0.313

2003 0.325

2004 0.309

2005 0.370

2006 0.345

2007 0.326

2008 0.334

2009 0.345

• The Solar Global is maximum in Summer period , with the angle solar Global = Direct*sin (h) +diffuse

• The low values of direct (cloud ) are compensated by solar elevation and diffuse in summer period.

• The diffuse are very low in winter period because of clear sky and visibility. In summer period , the diffuse is more important with cover sky and haze.

• The fraction Diffuse/Global is about 40 % in summer and 25 % in winter.

• The Global received at surface is 65-70 % the Extra-Terrestrial Radiation (ETR) on surface horizontal.

OFFSET OF PSP AND NIP

Offset of Night from 1 to 2 January 2009 : Winter Period ( cover sky = 3 Ci )

The offset of diffuse stay positive ( > 0 W/m2 ) about 13 mn after sunset. In the

Morning the offset become positive 7 mn before sun rise.

During the night , the values of offset of NIP and Diffuse are equal around

-2 W/m2 .

Offset of night 5 to 6 june 2009 : Summer period ( haze and cloudly )

The same remark of diffuse offset at sunset and sunrise.

The offset of diffuse and global decrease raipdly at 20 TU from -2 W/m2 to -8

W/m2. The NIP offset stay between -1 and -2 W/m2

Offset night : 1 to 2 january 2009

-10

-8

-6

-4

-2

0

2

4

6

1 61 121 181 241 301 361 421 481 541 601 661 721 781

time : sunset to sun rise

off

set

W/m

2

Diffuse NIP Global

Offset night : 5 to 6 june 2009

-12

-10

-8

-6

-4

-2

0

2

4

1 61 121 181 241 301 361 421 481 541 601

time :sunset to sunrise

off

set

W/m

2

Diffuse NIP Global

Radiation : 5 june 2010

-10

190

390

590

790

990

1 121 241 361 481 601 721 841 961 1081 1201 1321

time tu

PIR Diffuse NIP Global

Radiation in a hazy and cloudly day

The day of 05 june 2009 : hazy 4 km of visibility and very cloudly

Total daily : PIR (32.91 MJ),Dif (12.31MJ), NIP(8.91 MJ),GLB (19.52MJ)

Global = 49 % ETR

Dif/Glb = 63 %

Radiation : 25 january 2009

-200

0

200

400

600

800

1000

1200

1 99 197 295 393 491 589 687 785 883 981 1079 1177 1275 1373

time

PIR Diffus NIP Global

Radiation in a clear day with good visibility

The day 25 january 2009 : good visibility and no cloud

Total daily : PIR( 23.71 MJ) , DIF ( 2.05 MJ) , NIP ( 34.79 MJ) , GLB(20.67MJ)

GLB = 78 % ETR

DIF/GLB = 10 %

Calibration of PSP and NIP

Each year , between november to january , the calibration of PSP and NIP is made in situ at Tamanrasset with AHF N° 29225.

For PSP , we use the mehod : shade and unshade

G=direct*sinh + D

Knew= (G-D)/(direct*sinh) mv/wm-2

For NIP , the direct comparison between AHF and NIP

Variation of calibration coefficient

7

7.2

7.4

7.6

7.8

8

8.2

8.4

8.6

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Years : 2000-2010

Glb Dif Rg8 Nip

• The coefficients of global and diffuse decrease regulary since year 2000 with the an average of 1.7 % , the coefficient of global vary from 8.54 to 7.22 µv/wm-2 and for the diffuse from 8.34 to 7.01 µv/wm-2 in 10 years .

• The coefficient of NIP vary in the interval 7.74 to 7.80 , the original value is 7.77 µv/wm-2. It decrease to 7.74 and increase to 7.80 for last years .

• The variation of coefficient of RG8 is more obscure and not clear : the original value in september 1994 is 8.60 . One year the coefficient decrease and other it increase , in 15 years , the actual value is 8.24 µv/wm-2

INSTALLATION OF AN ALBEDOMETER

It is installed last 8 mars 2010 , at about 45 meters from

Datalogger . It is composed of 02 pyranometers Kipp§Zonnen with the calibration coefficients

Upper = 8.16 µv/wm-2 and Lower =7.86 µv/wm-2

This system is connected to the datalogger CR23X.

The values of upper PSP can be compared to the value of

global BSRN

Measure of global reflected and compute of Albedo

Albedometer at Tamanrasset since 8 mars 2010

Global Radiation and reflected of 11 mars 2010

-200

0

200

400

600

800

1000

1200

1 61 121 181 241 301 361 421 481 541 601 661 721 781 841 901 961 1021 10811141 1201 12611321 1381 1441

Time TU

Standard deviation of radiation 11 mars 2010

0

5

10

15

20

25

1 59 117 175 233 291 349 407 465 523 581 639 697 755 813 871 929 987 104 1103 11611219 127 133 139

Time tu

albedo from sunrise to sunset 11 mars 2010

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

1 61 121 181 241 301 361 421 481 541 601 661

radiation in the night : 10 to 11 mars 2010

-8

-6

-4

-2

0

2

4

1 61 121 181 241 301 361 421 481 541 601 661 721

time : from sunset to sunrise

off

set

in w

/m2

Glb BSRN GLB new Glb reflected

During the night , the reflected radiation is positive all time : near 0.5 w/m2 from sunset to 2230 tu , increase to 1.6 w/m2 the rest of the night .

The BSRN global and new global are nearly equal , except near noon where the BSRN global is higher .

The reflected radiation has the same shape with a rate of about 32 %. The Albedo = 0.32

MEASURE OF Aerosol Optical Depth ( AOD)

Since October 2006 , in collaboration with Spanish

Meteorology ( INM) and GAW station of IZANA ( Canaries)

Installation of a Cimel Photometer at Tamanrasset for

measure of AOD ( AERONET Project) .

Measure of AOD in 07 longwaves: 1020 nm, 870 , 675 , 500, 440, 380 , 340 nm.

• PHOTOMETER CIMEL ON THE ROOF OF METEOROLOGY CENTER TAMANRASSET

The AOD is minimum in winter period and very high in summer period

Daily variation of AOD (500 nm)

0

0.5

1

1.5

2

2.5

1 31 61 91 121 151 181 211 241 271 301 331 361 391 421 451 481 511 541 571 601 631 661 691 721

time : from 1/1/2008 to 31/12/2009