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Brewer measurements over UAE

12.9.2014, by Alexander Visser

The OZONE station was established at Abu Dhabi in UAE during July 1998 for measurement of Ozone amounts and Damaging Ultra-Violet (DUV) irradiance. This paper discusses Ozone distribution in the vertical as well as its seasonal variations. The seasonal and daily variations in DUV and its comparison with Ozone are also discussed.

Brewer Abu Dhabi, UAE

Article by Khalid Masood Syed, Meteorologist at the National Center of Meteorology & Seismology (NCMS), Ministry of Presidential Affairs (MOPA) in Abu Dhabi, UAE.

Abu Dhabi Ozone Station has started measurements of Ozone and DUV since July 1998 at its Ozone station in Abu Dhabi (Latitude 24.40° N Longitude 54.56°E). One Brewer spectrophotometer, MK II has been installed at Abu Dhabi Ozone station during July 1998. It measures total Ozone amount in the atmosphere with its vertical distribution, DUV and sulphur-di-oxide (S02). Dataset from June 1999 till 2010 is analyzed for this presentation. The results of the study of this data are presented in the following few paras.

Dr. Abdullah Al Mandous, Executive Director of National Center of Meteorology & Seismology (NCMS) has taken interest and upgraded Abu Dhabi Ozone Station with Brewer Spectrophotometer MK-III. In addition to that Mr. Yousef Al Kalbani, Director and Mr. Abdullah Alhammady, Head of Climate Section always support and appreciate of Brewer measurements. With the support of all of them NCMS has installed new Brewer Spectrophotometer MK III in its premises in February 2014..

Vertical distribution of Ozone

 Vertical distribution of Ozone is shown in figure 1. The maximum concentration of Ozone molecules is observed between 24-26 km above UAE, which comes to around 4 to 5 molecules of ozone per million molecules of air by volume (ppmv). However, most of the ozone in tropical atmosphere may be seen between 16 to 38 km above UAE.

Image1

Figure 1

 

Monthly distribution of total Ozone:

 Distribution of mean daily total ozone on monthly basis is shown in figure 2. This curve shows a minimum in the total ozone amount during winter month of January and maximum during summer month of July in the mean monthly ozone. Thus, the ozone maximum and minimum are both out of phase by one month from the zenith angle of the sun. Sun is almost overhead during June & maximum slant during December for UAE. This reveals a delayed equilibrium state of Ozone maximum & minimum amounts for UAE. This may be due to weak zonal stratospheric transport circulations during winter & stronger during summer in the lower stratosphere.

Slight departures from the smooth increase and decrease in monthly mean Ozone amounts may be seen during the spring month of March and autumn month of October. However, the two curves of absolute mean daily maximum and minimum total Ozone amounts in the same figure for corresponding months show some fluctuations, which may be attributable to the random fluctuations in the atmospheric waves and transport circulations in the lower stratosphere. Individual day increase / decrease in Ozone amounts were seen to be causing corresponding decrease / increase in DUV irradiance for those days.

Image2

Figure 2

 

Monthly distribution of Damaging Ultra Violet (DUV)

 The monthly distribution of Damaging Ultra Violet (DUV) is shown in figure 3. The maximum mean DUV incidence is seen to be during the summer month of June while the minimum during the winter month of December over UAE. It may be seen that rise in the DUV during winter to summer months is rather sharp as compared to fall in mean maximum DUV during summer to autumn.

Secondary maxima in the mean max DUV may be seen during spring month of March and autumn month of September which are coinciding with two equinoxes. Two more curves for maximum and minimum daily DUV also show peaks during the corresponding months (figure. 3). The fluctuations in these are consistent with the mean total ozone fluctuations during these months.

Image3

Figure 3

 

Diurnal Variation of DUV

 Diurnal Variation of DUV is shown in figure 4. The increase and decrease in the DUV is almost symmetrical with a peak around local noontime.

image4

Figure 4


Comparison of Mean Total Ozone with Mean DUV

 The monthly comparison of mean daily total Ozone with mean daily DUV is shown in figure 5. The humps and troughs in the two curves are almost in opposite phase. This shows that temporary increases in total ozone amount bring in corresponding decrease in DUV and vice versa. It may, however, be seen that Ozone maximum is coming during month of July and DUV maximum during June and Ozone minimum is in January while DUV minimum is during December.

Image5

Figure 5

 

 Conclusion

The vertical distribution of Ozone over UAE indicates maximum amounts over UAE at an altitude between 24-26 km, while most of Ozone is confined between 16 to 38 km altitudes over UAE. The monthly distribution of Ozone shows a displaced maximum and minimum by one month from the solar Zenith while DUV maximum & minimum are in phase with solar zenith. Maximum DUV irradiance is received during local noontime.

 

Khalid Masood Syed

Khalid Masood Syed

 

KHALID MASOOD SYED (E-mail: kmasood@ncms.ae), meteorologist, with 36 years of experience in most of the fields of Meteorology. Works at the National Center of Meteorology & Seismology (NCMS), Ministry of Presidential Affairs, Abu Dhabi – United Arab Emirates since the past 24 years. Received his Masters of Science (MSc) from the Karachi University–Pakistan and completed numerous of professional trainings in different countries. Dr. Khalid Masood Syed started his Meteorological career in 1978 at the Karachi-Airport, Pakistan Meteorological Department (PMD). After 12 years Syed moved to UAE and joined IAL-Abu Dhabi International Airport in 1990. In 1992 he joined UAE Meteorological Department, Ministry of Communications, Abu Dhabi. Since 2008 he works with the National Center of Meteorology & Seismology (NCMS), Ministry of Presidential Affairs, Abu Dhabi-UAE as an operational meteorologist in charge of Abu Dhabi’s Ozone Station. He is officially a Canadian resident and his family still lives in Toronto. He’s planning to move to Canada and is looking forward to continue his work experience with the Brewer.

Founder employee of Meteorological Department in UAE, played a significant role to establish almost all sections of Meteorological Department in UAE.

In July 1998, established and started working as an operational in-charge of Abu Dhabi Ozone Station with the Brewer Spectrophotometer MK-II & MK-III.

1992 – Played a significant role in the establishment of the Central Forecasting Office, Meteorological Department Ministry of Communications. Abu Dhabi – U.A.E-Under UNDP Project.

1993 – Participated in establishing the Climate Computing section, as a part of Meteorological Department, Ministry of Communication. Abu Dhabi – U.A.E-Under UNDP Project.

1998 – Established Abu Dhabi Ozone Station under the Meteorological Department, Ministry of Communications. Abu Dhabi – U.A.E-Under UNDP Project.

1998 – Developed Instruments Calibration Laboratory, as a part of Meteorological Department, Ministry of Communications. Abu Dhabi – U.A.E-Under UNDP Project.

2002 – 2011 – Implemented 20 AWS at different locations in U.A.E., as a part of National Center of Meteorology & Seismology Project under Ministry of Presidential Affairs. Abu Dhabi – U.A.E

2006 – Attended Expert Team Meeting AWS-4, 20-24 – Geneva Switzerland

2010 – Implemented one Automatic Weather Station (AWS). – Kazakhstan – Russia

 

Publications:

  • 1996 – Compiled / prepared tables, graphs / maps for the first publication on “U.A.E CLIMATE”, Publication Edition 1996. Abu Dhabi – U.A.E
  • 2005 – Prepared a Handbook for Guidelines & Principles on the “Meteorological Instruments and Methods of Observation”. Abu Dhabi – U.A.E.
  • Published Several Articles in Local English and Arabic Newspapers on Seasonal Variations of Ultraviolet (UV) and Ozone in UAE.

 

 

 

 

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