Brewer Data Management System (BDMS)
| "15-years of Brewer records at Hohenpeissenberg - A valuable supplement to the Dobson data set"
Ulf Koehler
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| First I would like to show the results of the comparison of the different total ozone instruments at Hohenpeissenberg, to give explanations and probable reasons for specific features (like annual course). Secondly I shall show, how these findings are used, to create a combined total ozone series from Dobson and Brewer, to improve the data base for statistical and climatological analyses. |
| "8 years of regular Brewer UV-observations at Hohenpeissenberg: instrumental and climatological results"
Ulf Koehler
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| I will like to present the findings of two colleagues, who have worked with the Brewer UV-data since the start of regular observations in 1990. Some instrumental features (e.g. change in the cosine response after prism alignment) and some statistical and climatological results (comparison with the radiation model STAR, spectral correlations between UV and total ozone, application of this results to estimate UV-trends in different wavelengths for the entire period of the total ozone observations 1967 until now) will be discussed. |
| O3 And UV-B Irradiance Measurements By Brewer N.067 At Rome Station
G.R. Casale, A.M. Siani, A. Aloe and S. Palmieri
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| Since 1992 O3 and UV-B measurements have been collected by means of Brewer n.067 located at Univ. of Rome. The stability of instrument is guaranteed through the control parameters and field intercalibration with the travelling standard. Daily direct sun ozone and UV-B observations are checked to put in evidence different temporal patterns. A comparison between Vigna di Valle station Dobson (50 km apart) and satellite data is presented. |
| Ozone and UV-B trends at Ispra from 1993 to 1997
F. Cappellani and C. Kochler
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An analysis of the ozone trend at Ispra (Italy) has been performed to ascertain if, even in a short time
period of five years (1993-1997), a decline of the monthly mean values of the total ozone column could be put in evidence. A linear
fit of the data displays a decrease of 0.21% per year with a mean value equal to 319.2 D.U.. A linear regression of the surface
monthly mean ozone values have been also performed showing a decreasing trend that could contribute, even if for a very small amount,
to the decline of the total ozone values. Ispra monthly mean total ozone data have been compared with those of three stations located
within 2 degrees latitude and 3 degrees longitude from Ispra (Haute Provence, Hohenpeissenberg and Arosa). A linear fit of the data
shows some discrepancies in the ozone trends attributable to the limited length of the observational period.
An analysis has been performed to verify if the trend of the monthly mean values of ozone at Ispra is in agreement with the trend of the solar UV measurements at a wavelength (305 nm) where the ozone absorption is still remarkable. The results, taken at a fixed solar zenith angle of 68(, show that the linear fit of the monthly mean values of UV is anticorrelated with the behaviour of the ozone column. |
| Ozone Variations in Eastern Siberia Observed by Brewer, SAOZ and ECC Ozone Sondes in 1992-1998.
V. Dorokhov
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It is widely recognized that during recent years, in the high and middle latitudes of the Northern
Hemisphere (NH), a statistically significant trend has been observed in total column and vertical
distribution of ozone. To date, several processes are being investigated which may be responsible
for the changing and reduced ozone amount in the stratosphere. In average in the NH the ozone column
is known to display a climatic maximum in the Eastern Siberia.
In order to investigate the behavior of atmospheric ozone in this area a Brewer #045 UV spectrophotometer (Yakutsk 62N, 132E) and SAOZ UV-VIS spectrometer (Zhigansk 67N, 127E) were installed here in 1992. Such disposition of instruments made it possible to cover a vast area in Eastern Siberia facing the most likely arrival of the Arctic polar vortex and investigate space and time ozone variations in this region. The abnormal ozone reduction events recently observed in Siberia and not always attributable to purely dynamic processes are of particular interest. To study the likely mechanisms of ozone depletion in this area observations of the vertical ozone distribution have been accomplished at Yakutsk aerological station using ECC ozone sondes. Results of ozone observations in 1992-1998 are shown and ozone variations in Eastern Siberia are discussed using ground-based, balloon-borne observational data and ECMWF meteorological and trajectories analyses. |
| Abnormal results of SL tests and it association with the deterioration of UG11 in the Brewer spectrophotometer
Zheng Xiangdong
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| In this paper, I will present the results of SL tests on Brewer#076 and Brewer#077 from the last two years. Abnormal SL results were discovered in 1996 on the two instruments. These abnormal SL results were caused by the deterioration of the UG11 filter which is located in the front of the PMT. Abnormal SL results have negative effects on the observations of ozone which will be presented. Some ways for preventing the UG11 filter from being damaged are also recommended in this paper. |
| Intercomparison of ozone vertical profiles between ECC ozonesonde and Brewer Umkehr made over Qinghai Plateau of China.
Liu Qijun, Zheng Xiangdong, Luo Chao, Tangjie, Ding Guoan, Li Xingshen and Zhou Xiuji
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| From October 1995 to August 1996, a total number of 50 ECC(Electronical Concentration Cell) ozonesoundings were lauched in Xinning city(36.43N, 101.45E, 2296m ASL) to study the distribution and seasonal characteristics of ozone vertical profiles, intercomparing the Brewer Umkher ozone profiles obtained at Waliguan baseline station(36.28N,100.82E,3816m ASL).The result of comparison shows that: (1)From 20 to 38km, the Umkher measurements produced more than 25% estimates of the ozone amount when compared with the ECC profiles, while from 23-33 km , the difference between Umkher's estimate and the ECC measurements is less than 15%. (2)High difference in the intercomaprisons occurred in the troposphere and lower stratosphere; and the ozone amounts were overestiamted in the Umkher layers 1, 2, 3, while were underestimated in Umkher layers 6, and layers7. |
| A Comparison of Brewer #025 and Dobson #061 Total Ozone and Umkehr Measurements Made at Boulder Between October 1991 and December 1997
G. L. Koenig, B. A. Bodhaine, S. J. Oltmans
M. A. Clark, R. D. Evans, D. M. Quincy
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Total ozone and Umkehr measurements made with Dobson #061 and Brewer #025 at Boulder, Colorado (40N) obtained over the period of October 1991
to December 1997 were compared. Since Dobson #061 is an automated instrument, more than 100 Umkehr profiles were available for each year
of the comparison period. Both instruments were compared to World Standard Dobson #083 and/or the secondary standard Dobson #065. Data
selection times, changes in calibration, and other instrumental factors were explored.
UV scans obtained on clear skies with Brewer #025 were examined. Time series of the erythemal irradiances and the total ozone were prepared. A regression of the total ozone and erythemal irradiance was performed to obtain radiative amplification factors. |
| Supporting software tools for Brewer data management
Karel Vanicek
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The Brewer spectrophotometer MKIV #098 has been operated at the Solar and Ozone Observatory of CHMI in Hradec Kralove since December 1993.
DS and ZS total ozone, SO2 and NO2 measurements and UVB scans are performed routinely in predefined schedules. To get an operational access to the data for
their listing, re-processing and export in real time, several software tools have been developed at SOO-HK. These make the following operations possible:
The external subroutines specified above are written for Windows95 environment and will be included into a compact software package. |
| Total ozone, UVB and Umkehr time series at Izaña
Alberto Redondas, Emilio Cuevas and Juanma Sancho
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| Since May 1991 total ozone, Umkehr profiles and UVB are being monitored at the Izaña Observatory with the Brewer#33 (MARK-II). The total ozone and UVB time series are shown as well as the different calibration and intercomparisons performed during the period 1991-98, which guarantee their quality control. In November 1992 started the ozonesounding program. Special attention will be paid to the Umkehr - ECC comparison (1993-97), and the main problems found at the Umkehr analysis will be discussed. Finally, the near future improvements in the total ozone and UV monitoring program will be advanced. |
| Eight years of Brewer UV-B measurements at Sodankylä, Finland
Kaisa Masson
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| In purpose of data verification the correlation coefficients between ozone and solar UV-irradiances were calculated for different solar zenith angles at 305 nm and 325 nm. This was done for the whole period 1990-1997 and separately for spring and summer time because of the differences in ground albedos. Preliminary UV trends were calculated at different wavelengths. |
| Use of the Brewer Ozone Spectrophotometer for Aerosol Optical Depth measurements in the Ultraviolet Region.
Fernanda R.S. Carvalho and Diamantino V. Henriques
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| The Brewer ozone spectrophotometer has been mainly used for automated measurements of total ozone and SO2 and global UV-B radiation. However, the power of this scientific instrument allows to perform another kind of interesting measurements in the UV region of the solar spectra, as for example the aerosol optical depth. This work shows a simple method to retrieve the aerosol optical depth using the Brewer measurements in the 5 operational wavelengths (306.3, 310.0, 313.5, 316.8 e 320.0 nm). In addition, it is also shown some results obtained at Lisbon and Funchal (Madeira Is.) portuguese ozone stations. |
| Zenith Total ozone observations with a Brewer instrument, including cloud corrections
Hugo De Backer
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| In Uccle the total ozone content of the atmosphere is measured since 1983 with Brewer spectrophotometer nr. 16. For observations on the direct sun, total ozone can be derived analytically. To handle the zenith observations an empirical method has to be implemented for each instrument and each location. In Uccle direct sun observations are often prevented by clouds. Therefore, special attention must be paid at the zenith sky observations. The zenith observations are separated in two groups, zenith blue and zenith cloudy. For the zenith blue values a polynomial is determined by a least squares method, using the data of quasi-simultaneous direct sun and zenith observations. For the observations with clouds, a correction, linear dependent on the total ozone content, is introduced. In this way the mean difference between daily means based on direct sun and on zenith observations is -0.1+/-1.5% for the Brewer instrument. The results are also compared with Dobson observations treated in the same way. |
| Total Ozone Derived From Irradiance Measurements With Brewer #42
Arne Dahlback and Finn Tonnessen
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| We have derived total ozone from irradiance measurements with our Brewer #42 in Oslo regularly since 1994. We use a modified ds routine where the radiation from the 5 standard wavelengths are redirected through the UV-B port. Derivation of total ozone from irradiance ratios was suggested by Stamnes et al. in 1991. The major advantage of this method is that the derived ozone is quite insensitive to cloud cover and no cloud corrections are required in most cases. We discuss the quality of ozone derived from irradiance measurements by comparing with standard Brewer/Dobson technique and with TOMS measurements. The irradiance method gives reliable ozone determination for solar zenith angles up to 80-85 degrees. |
| Zenith Sky Observations at Poprad-Ganovce
Miroslav Chmelik
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| Total atmospheric ozone measurements with Brewer#097 started at Poprad-Ganovce in August 1993. The ZS routine was only to measure in 19 % days. ZS results from the days without DS data are regularly used for various purposes. The reliability of ZS data is demonstrated from the DS-ZS differences before and after ZS optimization. The dependence of the DS-ZS difference on cloudiness, total ozone amount and airmass was investigated. These factors influence the yearly course of the DS-ZS difference. Typical yearly course has been observed for every processed year. The Poprad-Ganovce station considers to include the cloud, total ozone and MU corrections into ZS calculation to improve ZS data. |
