scholarly journals Comparison of OMI ozone and UV irradiance data with ground-based measurements at two French sites

2008 ◽  
Vol 8 (2) ◽  
pp. 4309-4351 ◽  
Author(s):  
V. Buchard ◽  
C. Brogniez ◽  
F. Auriol ◽  
B. Bonnel ◽  
J. Lenoble ◽  
...  
Keyword(s):  
Ozone Monitoring Instrument ◽  
Dose Rates ◽  
Clear Sky ◽  
The North ◽  
Uv Irradiance ◽  
Irradiance Data ◽  
Solar Uv ◽  
Sky Conditions ◽  
Rayonnement Solaire ◽  
Good Agreement

Abstract. Ozone Monitoring Instrument (OMI), launched in July 2004, is dedicated to the monitoring of the Earth's ozone, air quality and climate. OMI provides among other things the total column of ozone (TOC), the surface ultraviolet (UV) irradiance at several wavelengths, the erythemal dose rate and the erythemal daily dose. The main objective of this work is to validate OMI data with ground-based instruments in order to use OMI products (collection 2) for scientific studies. The Laboratoire d'Optique Atmosphérique (LOA) located in Villeneuve d'Ascq in the north of France performs solar UV measurements using a spectroradiometer and a broadband radiometer. The site of Briançon in the French Southern Alps is also equipped with a spectroradiometer operated by Interaction Rayonnement Solaire Atmosphère (IRSA). The instrument belongs to the Centre Européen Médical et Bioclimatologique de Recherche et d'Enseignement Supérieur. The comparison between the TOC retrieved with ground-based measurements and OMI TOC shows good agreement at both sites for all sky conditions. Comparisons of spectral UV on clear sky conditions are also satisfying whereas results of comparisons of the erythemal daily doses and erythemal dose rates for all sky conditions and for clear sky show that OMI overestimates significantly surface UV doses at both sites.

scholarly journals Comparison of OMI ozone and UV irradiance data with ground-based measurements at two French sites

2008 ◽  
Vol 8 (16) ◽  
pp. 4517-4528 ◽  
Author(s):  
V. Buchard ◽  
C. Brogniez ◽  
F. Auriol ◽  
B. Bonnel ◽  
J. Lenoble ◽  
...  
Keyword(s):  
Total Ozone ◽  
Relative Difference ◽  
Ozone Monitoring Instrument ◽  
Dose Rates ◽  
Clear Sky ◽  
The North ◽  
Uv Irradiance ◽  
Relative Differences ◽  
Sky Conditions ◽  
Better Than

Abstract. Ozone Monitoring Instrument (OMI), launched in July 2004, is dedicated to the monitoring of the Earth's ozone, air quality and climate. OMI is the successor of the Total Ozone Mapping Spectrometer (TOMS) instruments and provides among other atmospheric and radiometric quantities the total column of ozone (TOC), the surface ultraviolet (UV) irradiance at several wavelengths, the erythemal dose rates and the erythemal daily doses. The main objective of this work is to compare OMI data with data from ground-based instruments in order to use OMI products (collection 2) for scientific studies. The Laboratoire d'Optique Atmosphérique (LOA) located in Villeneuve d'Ascq (VdA) in the north of France performs solar UV measurements using a spectroradiometer. The site of Briançon in the French Southern Alps is also equipped with a spectroradiometer operated by Interaction Rayonnement Solaire Atmosphère (IRSA). The OMI total ozone column data is obtained from the OMI-TOMS and OMI-DOAS algorithms. The comparison between the TOC retrieved with ground-based measurements and OMI-TOMS data shows good agreement at both sites for all sky conditions with a relative difference for most of points better than 5%. For OMI-DOAS data, the agreement is generally better than 7% and these data show a significant dependence on solar zenith angle. Comparisons of spectral UV on clear sky conditions are also satisfying with relative differences smaller than 10% except at solar zenith angles larger than 65°. On the contrary, results of comparisons of the erythemal dose rates and erythemal daily doses for clear sky show that OMI overestimates surface UV doses at VdA by about 15% and that on cloudy skies, the bias increases. At Briançon, such a bias is observed if data corresponding to snow-covered surface are excluded.

scholarly journals Measurements of UV irradiance within the area of one satellite pixel

2008 ◽  
Vol 8 (18) ◽  
pp. 5615-5626 ◽  
Author(s):  
P. Weihs ◽  
M. Blumthaler ◽  
H. E. Rieder ◽  
A. Kreuter ◽  
S. Simic ◽  
...  
Keyword(s):  
Ozone Monitoring Instrument ◽  
Short Term ◽  
Uv Index ◽  
Clear Sky ◽  
Uv Irradiance ◽  
Instantaneous Values ◽  
The Mean ◽  
The Difference ◽  
Sky Conditions ◽  
Better Than

Abstract. A measurement campaign was performed in the region of Vienna and its surroundings from May to July 2007. Within the scope of this campaign erythemal UV was measured at six ground stations within a radius of 30 km. First, the homogeneity of the UV levels within the area of one satellite pixel was studied. Second, the ground UV was compared to ground UV retrieved by the ozone monitoring instrument (OMI) onboard the NASA EOS Aura Spacecraft. During clear-sky conditions the mean bias between erythemal UV measured by the different stations was within the measurement uncertainty of ±5%. Short term fluctuations of UV between the stations were below 3% within a radius of 20 km. For partly cloudy conditions and overcast conditions the discrepancy of instantaneous values between the stations is up to 200% or even higher. If averages of the UV index over longer time periods are compared the difference between the stations decreases strongly. The agreement is better than 20% within a distance of 10 km between the stations for 3 h averages. The comparison with OMI UV showed for clear-sky conditions higher satellite retrieved UV values by, on the average, approximately 15%. The ratio of OMI to ground measured UV lies between 0.9 and 1.5. and strongly depends on the aerosol optical depth. For partly cloudy and overcast conditions the OMI derived surface UV estimates show larger deviation from the ground-based reference data, and even bigger systematic positive bias. Here the ratio OMI to ground data lies between 0.5 and 4.5. The average difference between OMI and ground measurements is +24 to +37% for partly cloudy conditions and more than +50% for overcast conditions.

scholarly journals Measurements of UV irradiance within the area of one satellite pixel

2008 ◽  
Vol 8 (1) ◽  
pp. 3693-3720 ◽  
Author(s):  
P. Weihs ◽  
M. Blumthaler ◽  
H. E. Rieder ◽  
A. Kreuter ◽  
S. Simic ◽  
...  
Keyword(s):  
Reference Data ◽  
Ozone Monitoring Instrument ◽  
Uv Index ◽  
Clear Sky ◽  
Uv Irradiance ◽  
Ozone Monitoring ◽  
Time Periods ◽  
The Difference ◽  
Sky Conditions ◽  
Better Than

Abstract. A measurement campaign was performed in the region of Vienna and its surroundings from May to July 2007. Within the scope of this campaign erythemal UV was measured at six ground stations within a radius of 30 km. First, the homogeneity of the UV levels within the area of one satellite pixel was studied. Second, the ground UV was compared to ground UV retrieved by the ozone monitoring instrument (OMI) onboard the NASA EOS Aura Spacecraft. During clear sky conditions the difference in erythemal UV measured by the different stations was within the measurement uncertainty of 8%. For partly cloudy conditions and total overcast conditions the discrepancy of momentary values between the stations is up to 200% or even higher. If averages of the UV index over longer time periods are compared the difference between the stations decreases strongly. The agreement is better than 20% within a distance of 10 km between the stations for 3 h averages. The comparison with OMI UV showed for clear sky conditions higher satellite retrieved UV values by on the average approximately 15%. For partly cloudy and overcast conditions the OMI derived surface UV estimates show larger deviation from the ground-based reference data, and even bigger systematic positive bias.

scholarly journals Solar UV Irradiance Measurements at Four Sites in Tibet

1970 ◽  
Vol 8 (3) ◽  
pp. 75-86 ◽  
Author(s):  
Norsang Gelsor ◽  
Nima Pingcuo ◽  
Tsoja Wangmu ◽  
Berit Kjeldstad ◽  
Yi-Chun Chen ◽  
...  
Keyword(s):  
Dose Rates ◽  
Clear Sky ◽  
Data Analyses ◽  
Uv Irradiance ◽  
Eastern Tibet ◽  
Solar Uv ◽  
Solar Uv Irradiance ◽  
Uv Dose ◽  
Summer Time ◽  
Solar Ultraviolet

We present solar ultraviolet (UV) irradiance measurements at four sites in Tibet (Lhasa, Linzhi, Nagqu, and Tingri) for the period between July 2008 and September 2010. Erythemal UV dose rates and irradiances of solar UVA, UVB for all four sites are presented. Days with clear sky cloud transmittance (CLT) larger than 100% are particularly selected and analyzed for the four sites. Comparisons between the four sites are also carried out, and the clear-sky data analyses for the summer time show that Tingri (near Mt. Everest) has the highest UV irradiance, Lhasa the second highest, while Nagchu (Northen Tibet) and Linzhi (Eastern Tibet) have a bit lower values. Tingri has the strongest UV level among the four sites around the year, mainly due to increased albedo caused by snow-covered surroundings. UV data for Lhasa for the period from 2004 to 2010 are also analyzed, showing that the UV instantaneous irradiance trend for the recent six-year period is stable. However, the number of clear-sky days in Lhasa has increased over the recent six years, causing an increase in the yearly-integrated total UV irradiance. DOI: http://dx.doi.org/10.3126/jie.v8i3.5934 JIE 2011; 8(3): 75-86

Spectral solar UV irradiance data for cycle 21

2001 ◽  
Vol 106 (A10) ◽  
pp. 21569-21583 ◽  
Author(s):  
Matthew T. DeLand ◽  
Richard P. Cebula
Keyword(s):  
Uv Irradiance ◽  
Irradiance Data ◽  
Solar Uv ◽  
Solar Uv Irradiance

scholarly journals Comparison of OMI NO<sub>2</sub> observations and their seasonal and weekly cycles with ground-based measurements in Helsinki

2016 ◽  
Author(s):  
Iolanda Ialongo ◽  
Jay Herman ◽  
Nick Krotkov ◽  
Lok Lamsal ◽  
Folkert Boersma ◽  
...  
Keyword(s):  
Air Quality ◽  
Relative Difference ◽  
Urban Site ◽  
High Latitudes ◽  
Ozone Monitoring Instrument ◽  
Weekly Cycle ◽  
Clear Sky ◽  
Standard Product ◽  
Weekly Cycles ◽  
Sky Conditions

Abstract. We present the comparison of satellite-based OMI (Ozone Monitoring Instrument) NO2 products with ground-based observations in Helsinki. OMI NO2 total columns, available from standard product (SP) and DOMINO algorithm, are compared with the measurements performed by the Pandora spectrometer in Helsinki in 2012. The relative difference between Pandora #21 and OMI SP retrievals is 4 % and −6 % for clear sky and all sky conditions, respectively. DOMINO NO2 retrievals showed slightly lower total columns with median differences about −5 % and −14 % for clear sky and all sky conditions, respectively. Large differences often correspond to cloudy autumn-winter days with solar zenith angles above 65°. Nevertheless, the differences remain within the retrieval uncertainties. Furthermore, the weekly and seasonal cycles from OMI, Pandora and NO2 surface concentrations are compared. Both satellite- and ground-based data show a similar weekly cycle, with lower NO2 levels during the weekend compared to the weekdays as result of reduced emissions from traffic and industrial activities. Also the seasonal cycle shows a similar behaviour, even though the results are affected by the fact that most of the data are available during spring-summer because of cloud cover in other seasons. This is one of few works in which OMI NO2 retrievals are evaluated in a urban site at high latitudes (60° N). Despite the city of Helsinki having relatively small pollution sources, OMI retrievals have proved to be able to describe air quality features and variability similar to surface observations. This adds confidence in using satellite observations for air quality monitoring also at high latitudes.

Coupling Groundwater, Vegetation, and Atmospheric Processes: A Comparison of Two Integrated Models

2017 ◽  
Vol 18 (5) ◽  
pp. 1489-1511 ◽  
Author(s):  
Mauro Sulis ◽  
John L. Williams ◽  
Prabhakar Shrestha ◽  
Malte Diederich ◽  
Clemens Simmer ◽  
...  
Keyword(s):  
Land Surface ◽  
Convective Precipitation ◽  
Atmospheric Processes ◽  
Clear Sky ◽  
The North ◽  
Western Germany ◽  
The Difference ◽  
Heat And Moisture ◽  
Sky Conditions ◽  
Diagram Approach

Abstract This study compares two modeling platforms, ParFlow.WRF (PF.WRF) and the Terrestrial Systems Modeling Platform (TerrSysMP), with a common 3D integrated surface–groundwater model to examine the variability in simulated soil–vegetation–atmosphere interactions. Idealized and hindcast simulations over the North Rhine–Westphalia region in western Germany for clear-sky conditions and strong convective precipitation using both modeling platforms are presented. Idealized simulations highlight the strong variability introduced by the difference in land surface parameterizations (e.g., ground evaporation and canopy transpiration) and atmospheric boundary layer (ABL) schemes on the simulated land–atmosphere interactions. Results of the idealized simulations also suggest a different range of sensitivity in the two models of land surface and atmospheric parameterizations to water-table depth fluctuations. For hindcast simulations, both modeling platforms simulate net radiation and cumulative precipitation close to observed station data, while larger differences emerge between spatial patterns of soil moisture and convective rainfall due to the difference in the physical parameterization of the land surface and atmospheric component. This produces a different feedback by the hydrological model in the two platforms in terms of discharge over different catchments in the study area. Finally, an analysis of land surface and ABL heat and moisture budgets using the mixing diagram approach reveals different sensitivities of diurnal atmospheric processes to the groundwater parameterizations in both modeling platforms.

Status of UARS solar UV irradiance data

2004 ◽  
Vol 34 (2) ◽  
pp. 243-250 ◽  
Author(s):  
M.T DeLand ◽  
L.E Floyd ◽  
G.J Rottman ◽  
J.M Pap
Keyword(s):  
Uv Irradiance ◽  
Irradiance Data ◽  
Solar Uv ◽  
Solar Uv Irradiance

scholarly journals Total Column Water Vapour Retrieval from S-5P/TROPOMI in the Visible Blue Spectral Range

2020 ◽  
Author(s):  
Christian Borger ◽  
Steffen Beirle ◽  
Steffen Dörner ◽  
Holger Sihler ◽  
Thomas Wagner
Keyword(s):  
Water Vapour ◽  
Spectral Range ◽  
Input Data ◽  
Reference Data ◽  
Boreal Summer ◽  
Data Sets ◽  
Clear Sky ◽  
Sky Conditions ◽  
Total Column ◽  
Good Agreement

Abstract. Total column water vapour has been retrieved from TROPOMI measurements in the visible blue spectral range and compared to a variety of different reference data sets for clear-sky conditions during boreal summer and winter. The retrieval consists of the common two-step DOAS approach: first the spectral analysis is performed within a linearized scheme and then the retrieved slant column densities are converted to vertical columns using an iterative scheme for the water vapour a priori profile shape which is based on an empirical parameterization of the water vapour scale height. Moreover, a modified albedo map was used combining the OMI LER albedo and scaled MODIS albedo map. The use of the alternative albedo is especially important over regions with very low albedo and high probability of clouds like the Amazon region. The errors of the TCWV retrieval have been theoretically estimated considering the contribution of a variety of different uncertainty sources. For observations during clear-sky conditions, over ocean surface, and at low solar zenith angles the error typically is around values of 10–20 % and during cloudy-sky conditions, over land surface, and at high solar zenith angles it reaches values around 20–50 %. In the framework of a validation study the retrieval demonstrates that it can well capture the global water vapour distribution: the retrieved H2O VCDs show very good agreement to the reference data sets over ocean for boreal summer and winter whereby the modified albedo map substantially improves the retrieval's consistency to the reference data sets in particular over tropical landmasses. However over land the retrieval underestimates the VCD by about 10 %, particularly during summertime. Our investigations show that this underestimation is likely caused by uncertainties within the surface albedo and the cloud input data: Low level clouds cause an underestimation but for mid to high level clouds good agreement is found. In addition, our investigations indicate that these biases can probably be further reduced by the use of updated cloud input data. The TCWV retrieval can be easily applied to further satellite sensors (e.g. GOME-2 or OMI) for creating uniform measurement data sets on longterm which is particularly interesting for climate and trend studies of water vapour.

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