scholarly journals The Influence of Rainfall and Temperature on Total Column Ozone over West Africa

2017 ◽  
Vol 10 (2) ◽  
pp. 1-11 ◽  
Author(s):  
E Eresanya ◽  
A Oluleye ◽  
M Daramola
Keyword(s):  
West Africa ◽  
Total Column Ozone ◽  
Column Ozone ◽  
Total Column

scholarly journals Assessing the Influence of Inter Tropical Discontinuity on Total Column Ozone Variation Over West Africa

2021 ◽  
Author(s):  
Ayomide Victor Arowolo ◽  
Ayodeji Oluleye
Keyword(s):  
West Africa ◽  
Pearson Correlation ◽  
Kendall Test ◽  
Relevant Information ◽  
Total Column Ozone ◽  
Study Region ◽  
Dewpoint Temperature ◽  
Column Ozone ◽  
The Relationship ◽  
Total Column

Abstract The focus of this study is to evaluate the influence of Intertropical Discontinuity (ITD) on the variation of Total column ozone (TCO). Relevant information is supplied on the temporal and spatial variability of TCO along the ITD zone, which is an important factor influencing the earth's atmosphere. Several studies over the years have established the relationship and influence several atmospheric processes have on TCO. However, the relationship between Intertropical discontinuity and TCO over West Africa has a gap. This study tends to examine the influence ITD has on TCO variation using the West Africa region as a case study. The study used Wind, ozone and dewpoint temperature data for the period between 1980-2019. To assess the variability and trend over the study region, several statistical methods were used, including Pearson correlation, Mann-Kendall, and linear regression model. The Mann-Kendall test shows an increasing trend throughout the months over the study region. Spatial analysis also revealed that regions North of the ITD has a higher concentration of TCO that the southern region of the ITD. however, ITD influence was more visible during the wet month of June to August (JJA) as the highest concentration of TCO was observed during this period across all latitude but more deviation was observed between latitude 100N to 180N, while the least occurrence is observed when ITD is at its minimum position in the month of December to February (DJF). The ACRV shows that 140N exhibit the highest variation with a value of 4.84, while the deviation is also at its highest with value of 13.65. The monthly position of ITD for Forty years was also analysed to observe the monthly deviation along the ITD region forty years and the spatial distribution of TCO was analysed from January to December. It’s of note that during the cause of this study, ozone hole which is designated by concentration less than or equal to 220DU was not recorded. The highest and the lowest value of TCO is 295DU and 227DU respectively with an average range of 68DU.

scholarly journals Spatial mapping of ground-based observations of total ozone

2015 ◽  
Vol 8 (10) ◽  
pp. 4487-4505 ◽  
Author(s):  
K.-L. Chang ◽  
S. Guillas ◽  
V. E. Fioletov
Keyword(s):  
Spatial Interpolation ◽  
Stochastic Partial Differential Equation ◽  
Positive Impact ◽  
The Novel ◽  
Total Column Ozone ◽  
Column Ozone ◽  
Source Of Information ◽  
Total Column ◽  
Ozone Levels

Abstract. Total column ozone variations estimated using ground-based stations provide important independent source of information in addition to satellite-based estimates. This estimation has been vigorously challenged by data inhomogeneity in time and by the irregularity of the spatial distribution of stations, as well as by interruptions in observation records. Furthermore, some stations have calibration issues and thus observations may drift. In this paper we compare the spatial interpolation of ozone levels using the novel stochastic partial differential equation (SPDE) approach with the covariance-based kriging. We show how these new spatial predictions are more accurate, less uncertain and more robust. We construct long-term zonal means to investigate the robustness against the absence of measurements at some stations as well as instruments drifts. We conclude that time series analyzes can benefit from the SPDE approach compared to the covariance-based kriging when stations are missing, but the positive impact of the technique is less pronounced in the case of drifts.

scholarly journals Characterizing ozone throughout the atmospheric column over the tropical Andes from in situ and remote sensing observations

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
María Cazorla ◽  
René Parra ◽  
Edgar Herrera ◽  
Francisco Raimundo da Silva
Keyword(s):  
Boundary Layer ◽  
Atmospheric Ozone ◽  
Tropical Andes ◽  
Total Column Ozone ◽  
Study Region ◽  
Boundary Layer Height ◽  
Mixing Ratios ◽  
The Andes ◽  
Column Ozone ◽  
Total Column

In this study, we characterize atmospheric ozone over the tropical Andes in the boundary layer, the free troposphere, and the stratosphere; we quantify each contribution to total column ozone, and we evaluate the performance of the multi-sensor reanalysis (MSR2) in the region. Thus, we present data taken in Ecuador and Peru (2014–2019). The contribution from the surface was determined by integrating ozone concentrations measured in Quito and Cuenca (Ecuador) up to boundary layer height. In addition, tropospheric and stratospheric column ozone were quantified from ozone soundings (38) launched from Quito during the study time period. Profiles were compared against soundings at Natal (SHADOZ network) for being the closest observational reference with sufficient data in 2014–2019. Data were also compared against stratospheric mixing ratios from the Aura Microwave Limb Sounder (Aura MLS). Findings demonstrate that the stratospheric component of total column ozone over the Andes (225.2 ± 8.9 Dobson Units [DU]) is at similar levels as those observed at Natal (223.3 ± 8.6 DU), and observations are comparable to Aura MLS data. In contrast, the tropospheric contribution is lower over the Andes (20.2 ± 4.3 DU) when compared to Natal (35.4 ± 6.4 DU) due to a less deep and cleaner troposphere. From sounding extrapolation of Quito profiles down to sea level, we determined that altitude deducts about 5–7 DU from the total column, which coincides with a 3%–4% overestimation of the MSR2 over Quito and Marcapomacocha (Peru). In addition, when MSR2 data are compared along a transect that crosses from the Amazon over Quito, the Ecuadorian coast side, and into the Pacific, observations are not significantly different among the three first locations. Results point to coarse reanalysis resolution not being suitable to resolve the formidable altitude transition imposed by the Andes mountain chain. This work advances our knowledge of atmospheric ozone over the study region and provides a robust time series of upper air measurements for future evaluations of satellite and reanalysis products.

scholarly journals Comparison of profile total ozone from SBUV(v8.6) with GOME-type and ground-based total ozone for 16-yr period (1996 to 2011)

2013 ◽  
Vol 6 (6) ◽  
pp. 10081-10115 ◽  
Author(s):  
E. W. Chiou ◽  
P. K. Bhartia ◽  
R. D. McPeters ◽  
D. G. Loyola ◽  
M. Coldewey-Egbers ◽  
...  
Keyword(s):  
Strong Evidence ◽  
Total Ozone ◽  
Time Dependent ◽  
Total Column Ozone ◽  
Monthly Data ◽  
Latitude Band ◽  
Ozone Data ◽  
Standard Deviations ◽  
Column Ozone ◽  
Total Column

Abstract. This paper describes the comparison of the variability of total column ozone inferred from the three independent multi-year data records, namely, (i) SBUV(v8.6) profile total ozone, (ii) GTO(GOME-Type total ozone), and (iii) Ground-based total ozone data records covering the 16-yr overlap period (March 1996 through June 2011). Analyses are conducted based on area weighted zonal means for (0–30° S), (0–30° N), (50–30° S), and (30–60° N). It has been found that on average, the differences in monthly zonal mean total ozone vary between −0.32 to 0.76 % and are well within 1%. For "GTO minus SBUV", the standard deviations and ranges (maximum minus minimum) of the differences regarding monthly zonal mean total ozone vary between 0.58 to 0.66% and 2.83 to 3.82% respectively, depending on the latitude band. The corresponding standard deviations and ranges regarding the differences in monthly zonal mean anomalies show values between 0.40 to 0.59% and 2.19 to 3.53%. The standard deviations and ranges of the differences "Ground-based minus SBUV" regarding both monthly zonal means and anomalies are larger by a factor of 1.4 to 2.9 in comparison to "GTO minus SBUV". The Ground-based zonal means, while show no systematic differences, demonstrate larger scattering of monthly data compared to satellite-based records. The differences in the scattering are significantly reduced if seasonal zonal averages are analyzed. The trends of the differences "GTO minus SBUV" and "Ground-based minus SBUV" are found to vary between −0.04 and 0.12% yr−1 (−0.11 and 0.31 DU yr−1). These negligibly small trends have provided strong evidence that there are no significant time dependent differences among these multi-year total ozone data records. Analyses of the deviations from pre-1980 level indicate that for the overlap period of 1996 to 2010, all three data records show gradual recovery at (30–60° N) from −5% in 1996 to −2% in 2010. The corresponding recovery at (50–30° S) is not as obvious until after 2006.

scholarly journals Total column ozone and solar UV-B erythemal irradiance over Kishinev, Moldova

2013 ◽  
Vol 8 (3) ◽  
pp. 204-209
Keyword(s):  
Mean Value ◽  
Ozone Content ◽  
Solar Ultraviolet Radiation ◽  
Total Column Ozone ◽  
Mean Values ◽  
Ozone Trend ◽  
Solar Uv ◽  
Column Ozone ◽  
Autumn And Winter ◽  
Total Column

Results of the total column ozone and ultraviolet (UV-B) erythemally weighted irradiance measurements at the ground-based solar monitoring station at the Kishinev (Moldova) are presented. Diffuse and global components of solar UV-B erythemal irradiance on horizontal plane were continuously measured with sensors UV-S-B-C (of broadband 280-315 nm), Kipp&Zonen. Monthly totals of global and diffuse components of solar UV-B erythemal radiation reveal distinct seasonal variation with respective minimum in winter and maximum in summer. Typical values for these components in limiting cases are presented. A simple polynomial relationship between the global and diffuse components of solar UV-B erythemal radiation measured for cloudless days was derived. It was shown that coefficients of the polynomial depend on daily mean value of aerosol optical thickness (AOT). Collocated measurements of AOT have been carried out with the sunphotometer Cimel CE-318 within the framework of the Aerosol Robotic Network (AERONET) program, managed by NASA/GSFC. Total column ozone content was retrieved from direct solar ultraviolet radiation measurements at 3 discrete wavelengths centered at 305.5, 312.5, and 320 nm within the UV-B range. Ozone measurements were regularly carried out with the hand-held MICROTOPS II Ozonemeter, Solar Light Co. Monthly average values of total column ozone content measured with the MICROTOPS II at the Kishinev are in close agreement with those ones retrieved from the multiyear (1978-2004) database statistics acquired from satellite platforms measurements with the Total Ozone Mapping Spectrometer (TOMS). It was shown the existence of seasonal variability of the total column ozone content with respective minimum values observed at the end of autumn and winter, and maximum values observed at the end of winter and in spring. The maximum and minimum of daily mean values of total column ozone ever measured with TOMS at the satellite platforms overpassed Kishinev site, amounted of ~540 DU (on February 19, 1985) and ~204 DU (on December 1, 1999). Yearly mean value of total column ozone measured at the Kishinev was ~ 338 DU. Total column ozone measurements carried out with MICROTOPS at the Kishinev site from September 2003 to August 2004, gave maximum and minimum values of ozone daily means at ~ 489 DU (on February 12, 2004) and ~259 DU (on December 3, 2003). The estimation of total column ozone trend derived from the TOMS multi-year statistics was ~ -10 DU/decade.

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