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Operation and results of spectrophotometric measurements with a - - PowerPoint PPT Presentation

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Operation and results of spectrophotometric measurements with a high temporal resolution at the observatory of IMCES Smirnov S. V. Institute of Monitoring of Climatic and Ecological Systems SB RAS, Tomsk ENVIROMIS-2008, June 28 - July 5,

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Operation and results of spectrophotometric measurements with a high temporal resolution at the

  • bservatory of IMCES

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Smirnov S. V. Institute of Monitoring of Climatic and Ecological Systems SB RAS, Tomsk

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Background

Ozone and UV solar radiation are a key atmospheric constituents in atmospheric chemistry. In the stratosphere ozone acts as an absorber of UV radiation, providing a UV shield for the Earth, as well as an energy source. UV radiation in turn is an important parameter in atmospheric chemistry and plays a key role in environmental and climatic problems associated with tropospheric chemistry and air quality, stratospheric chemistry and ozone depletion, bioproductivity and human health, and chemistry-climate interactions.

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Main Research Needs

Global Monitoring for Environment and Security (GMES) PROtocol MOniToring for the GMES Service Element: Atmosphere (PROMOTE) Science Review for Ozone, UV, Air Quality, Greenhouse Gases and Aerosol, 2006

n Both monitoring and forecasting of UV irradiance and spectral

fluxes on a surface, there is in urgent need of improved data that adequately take into account UV attenuation by clouds and aerosols.

n Although cloud effects are understood theoretically, the quality

  • f forecasting and monitoring is still limited by uncertainties of

input parameters. This is especially caused by the spatio- temporal variability and inhomogeneity of clouds, as well as the complex radiative interaction of UV radiation between clouds, aerosol, surface, phytome and the human skin.

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Approach

n To operate spectrophotometric UV observations with a high

temporal resolution ⇒ to minimize uncertainties in

  • bservational data, as well as to analyze the short-term and fast

UV variations (oscillations)

n To perform UV observations in complex with other atmospheric

  • bservations including meteorological, actinometrical and

electrical measurements ⇒ to analyze the interaction of UV radiation with different atmospheric parameters The investigations are carried out within the framework of project SB RAS # 7.10.1.1 «Investigation of atmospheric processes forming the climate with allowance for global and regional climatic effects».

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Location

Measurements of solar UV radiation are performed at the

  • bservatory (56.48°N, 85.05°E, 193 m a. s. l.) of IMCES SB RAS

since March, 2006 with multichannel moderate-bandwidth filter NILU-UV-6T radiometer # 04117.

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Instrument

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The radiometer measures UV irradiances at five channels with center wavelengths at 302, 312, 320, 340 and 380 nm. The channel bandwidths are approximately 10 nm at FWHM. In addition, a sixth channel measures photosynthetic active radiation (PAR) in the wavelength region 400−700 nm. The

  • ptical part of the instrument consists of a Teflon diffuser,

silicon detectors and high quality band-pass filters.

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Instrument

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The instrument has a built-in circular data logger with capacity of storing 3 weeks of one-minute averages of the measured irradiances and the detector temperature. A data acquisition software transfers measured raw data to the computer hard disk and can display on-line raw data as well as historical raw data. A data processing software calculates the mean and maximum dose rates and integrated daily dose of UV-A (315-400 nm), UV- B (280-315 nm), FAR, СIE- and CLW-weighted irradiance. The software also provides cloud cover assessment and total

  • zone column.

Besides absolute calibrations performed by the NILU, the instrument is calibrated with lamp calibrator on a regular basis in place.

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 20 40 60 80 100

2006 2007 2008 Mean daily cloud transmission at 380 nm [%] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 2 4 6 8 200 250 300 350 400 450 500 550

2006 2007 2008 SD [DU] Mean daily total ozone [DU] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Measurement Results

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

1 31 61 91 121 151 181 211 241 271 301 331 361 0,0 2,0x10

5

4,0x10

5

6,0x10

5

8,0x10

5

1,0x10

6

1,2x10

6

1,4x10

6

1,6x10

6

2006 2007 2008 Integrated daily dose of UV-A [J/m^2] Day of year from March 27, 2006 to June 21, 2008

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Measurement Results

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

1 31 61 91 121 151 181 211 241 271 301 331 361 10 20 30 40 50

2006 2007 2008 Mean daily dose rate of UV-A [W/m^2] Day of year from March 27, 2006 to June 21, 2008

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 2,0x10

4

4,0x10

4

6,0x10

4

8,0x10

4

2006 2007 2008 Integrated daily dose of UV-B [J/m^2] Day of year from March 27, 2006 to June 21, 2008

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Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5

2006 2007 2008 Mean daily dose rate of UV-B [W/m^2] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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400 450 500 550 600 650 700 2,0x10

  • 6

3,0x10

  • 6

4,0x10

  • 6

5,0x10

  • 6

6,0x10

  • 6

From: http://www.biospherical.com/nsf/login/GUV/PAR_convert_uW_per_cm2nm_to_uE_per_cm2sec.txt

Coefficient Wavelength [nm]

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Action spectrum used for convertation the PAR units from µW/(cm²⋅nm) to µE/(cm²⋅s)

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Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 1x10

7

2x10

7

3x10

7

4x10

7

5x10

7

2006 2007 2008 Integreted daily dose of PAR [µE/m^2] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 200 400 600 800 1000 1200 1400 1600

2006 2007 2008 Mean daily dose rate of PAR [µE/(s⋅m^2)] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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285 290 295 300 305 310 315 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7

From: http://www.biospherical.com/nsf/login/GUV/Caldwell.txt

Action spectrum suggested by: Caldwell, M. M. (1971). Solar UV irradiation and the growth and development of higher plants // In: Photophysiology, edited by A.C. Giese, Vol. 6,

  • Ch. 4, pp. 131 - 177

Spectrum was parameterized based on Equation (24) in: Green, A. E. S., T. Sawada, and E. P. Shettle (1974). The middle ultraviolet reaching the ground // Photochemistry and Photobiology, Vol 19., pp. 251-259: A = 2.618*(1-(w/313.3)^2)*exp((300-w)/31.08), where w is wavelength in nm. Caldwell defines the action spectrum as "relative photon effectiveness". The spectrum is used "as is", without converting it to energy units. Dose rates derived with this action spectrum are labeled "Caldwell". Integration range: 286 - 313 nm

Relative Effectiveness Wavelength [nm]

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Generalized plant (biological) action spectrum

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1 31 61 91 121 151 181 211 241 271 301 331 361 1x10

3

2x10

3

3x10

3

4x10

3

5x10

3

2006 2007 2008 Integrated daily dose of CLW-weighted UV [J/m^2] Day of year from March 27, 2006 to June 21, 2008

Measurement Results

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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1 31 61 91 121 151 181 211 241 271 301 331 361 0,00 0,05 0,10 0,15 0,20 0,25

2006 2007 2008 Mean daily dose rate of CLW-weighted UV [W/m^2] Day of year from March 27, 2006 to June 21, 2008

Measurement Results

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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The CIE action spectrum is a model for the susceptibility of the Caucasian skin to sunburn (reddening of the skin; erythema). It was proposed by McKinlay & Diffey (1987) and adopted as a standard by the Commission Internationale de l'Éclairage (International Commission on Illumination).

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

CIE-weighted irradiance is the erythemally effective UV radiation. Of the global UV radiation at the ground, 94% is UV-A, 6% is UV-B. Of the erythemal UV irradiance, however, 17% is UV-A, 83% is UV-B.

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1 31 61 91 121 151 181 211 241 271 301 331 361 1x10

3

2x10

3

3x10

3

4x10

3

2006 2007 2008 Integrated daily dose of CIE-weighted UV [J/m^2] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Measurement Results

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1 31 61 91 121 151 181 211 241 271 301 331 361 0,00 0,05 0,10 0,15 0,20

2006 2007 2008 Mean daily dose rate of CIE-weighted UV [W/m^2] Day of year from March 27, 2006 to June 21, 2008

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

Measurement Results

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Analysis Results

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

n

The first obtained results of measurements showed that low

  • zone column amounts and clean atmospheres are main

factors that contribute to the high UV levels.

n

On the average the variable cloud cover in Tomsk reduced the daily integrated erythemal UV dose by 20−30 %.

n

The mean difference between daily total ozone column amounts derived from NILU-UV measurements and from OMI– EOS Aura was at most ±5 %.

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Aspects

ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

n

To execute the proper quality control of the measurements and quality assurance of the data, which are basis of all scientific use of data

n

To execute the broad statistical and mathematical analysis of the data

n

To enhance the instrumentation, in particular an exposure of the sun photometer for spectral measurements of aerosol

  • ptical thickness, second NILU-UV radiometer, all-sky digital

camera

n

To output the data in internet space

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ENVIROMIS-2008, June 28 - July 5, 2008, Tomsk, Russia

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