scholarly journals Spatial and temporal variability of tropospheric ozone (O3) in the boundary layer above the Aegean Sea (eastern Mediterranean)

2002 ◽  
Vol 107 (D18) ◽  
Author(s):  
G. Kouvarakis
Keyword(s):  
Boundary Layer ◽  
Temporal Variability ◽  
Tropospheric Ozone ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Spatial And Temporal Variability

scholarly journals CO<sub>2</sub> dispersion modelling over Paris region within the CO<sub>2</sub>-MEGAPARIS project

2013 ◽  
Vol 13 (9) ◽  
pp. 4941-4961 ◽  
Author(s):  
C. Lac ◽  
R. P. Donnelly ◽  
V. Masson ◽  
S. Pal ◽  
S. Riette ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Temporal Variability ◽  
Urban Areas ◽  
Onset Time ◽  
Urban Canopy ◽  
Horizontal Resolution ◽  
Spatial And Temporal Variability ◽  
Good Representation ◽  
Mixing Ratios ◽  
Urban Rural

Abstract. Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is a challenging and interesting task needed to be performed in order to utilise CO2 measurements in an atmospheric inverse framework and to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town Energy Balance (TEB) urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs) surface scheme, allowing a full interaction of CO2 modelling between the surface and the atmosphere. Statistical scores show a good representation of the urban heat island (UHI) with stronger urban–rural contrasts on temperature at night than during the day by up to 7 °C. Boundary layer heights (BLH) have been evaluated on urban, suburban and rural sites during the campaign, and also on a suburban site over 1 yr. The diurnal cycles of the BLH are well captured, especially the onset time of the BLH increase and its growth rate in the morning, which are essential for tall tower CO2 observatories. The main discrepancy is a small negative bias over urban and suburban sites during nighttime (respectively 45 m and 5 m), leading to a few overestimations of nocturnal CO2 mixing ratios at suburban sites and a bias of +5 ppm. The diurnal CO2 cycle is generally well captured for all the sites. At the Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the atmospheric boundary layer (ABL) growth reaches the measurement height. At suburban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a strong spatio-temporal variability. A sensitivity test without urban parameterisation removes the UHI and underpredicts nighttime BLH over urban and suburban sites, leading to large overestimation of nocturnal CO2 mixing ratio at the suburban sites (bias of +17 ppm). The agreement between observation and prediction for BLH and CO2 concentrations and urban–rural increments, both day and night, demonstrates the potential of using the urban mesoscale system in the context of inverse modelling

Spatial and temporal variability of 210Po and 210Pb in mussels (Mytilus galloprovincialis) at the Turkish coast of the Aegean Sea

Chemosphere ◽  
2011 ◽  
Vol 83 (8) ◽  
pp. 1102-1107 ◽  
Author(s):  
Aysun Uğur ◽  
Banu Özden ◽  
Işık Filizok
Keyword(s):  
Temporal Variability ◽  
Mytilus Galloprovincialis ◽  
Aegean Sea ◽  
Spatial And Temporal Variability

Spatial and Temporal Variability of Tropospheric Ozone over Europe

1997 ◽  
pp. 35-64 ◽  
Author(s):  
H. E. Scheel ◽  
G. Ancellet ◽  
H. Areskoug ◽  
J. Beck ◽  
J. Bösenberg ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Tropospheric Ozone ◽  
Spatial And Temporal Variability

scholarly journals Atmospheric deposition of inorganic phosphorus in the Levantine Basin, eastern Mediterranean: Spatial and temporal variability and its role in seawater productivity

2003 ◽  
Vol 48 (4) ◽  
pp. 1557-1568 ◽  
Author(s):  
Z. Markaki ◽  
K. Oikonomou ◽  
M. Kocak ◽  
G. Kouvarakis ◽  
A. Chaniotaki ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Temporal Variability ◽  
Eastern Mediterranean ◽  
Inorganic Phosphorus ◽  
Spatial And Temporal Variability ◽  
Levantine Basin

scholarly journals Aircraft observations since the 1990s reveal increases of tropospheric ozone at multiple locations across the Northern Hemisphere

2020 ◽  
Vol 6 (34) ◽  
pp. eaba8272 ◽  
Author(s):  
Audrey Gaudel ◽  
Owen R. Cooper ◽  
Kai-Lan Chang ◽  
Ilann Bourgeois ◽  
Jerry R. Ziemke ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Temporal Variability ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Monitoring Network ◽  
Spatial And Temporal Variability ◽  
Commercial Aircraft ◽  
Aircraft Observations ◽  
Ozone Precursor ◽  
Satellite Product

Tropospheric ozone is an important greenhouse gas, is detrimental to human health and crop and ecosystem productivity, and controls the oxidizing capacity of the troposphere. Because of its high spatial and temporal variability and limited observations, quantifying net tropospheric ozone changes across the Northern Hemisphere on time scales of two decades had not been possible. Here, we show, using newly available observations from an extensive commercial aircraft monitoring network, that tropospheric ozone has increased above 11 regions of the Northern Hemisphere since the mid-1990s, consistent with the OMI/MLS satellite product. The net result of shifting anthropogenic ozone precursor emissions has led to an increase of ozone and its radiative forcing above all 11 study regions of the Northern Hemisphere, despite NOx emission reductions at midlatitudes.

scholarly journals CO<sub>2</sub> dispersion modelling over Paris region within the CO<sub>2</sub>-MEGAPARIS project

2012 ◽  
Vol 12 (10) ◽  
pp. 28155-28193 ◽  
Author(s):  
C. Lac ◽  
R. P. Donnelly ◽  
V. Masson ◽  
S. Pal ◽  
S. Donier ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Temporal Variability ◽  
Urban Areas ◽  
Onset Time ◽  
Urban Canopy ◽  
Co2 Concentration ◽  
Horizontal Resolution ◽  
Spatial And Temporal Variability ◽  
Good Representation ◽  
Urban Sites

Abstract. Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is challenging, but essential in order to utilize CO2 measurements in an atmospheric inverse framework to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration, during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town-Energy Balance (TEB) urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs) surface scheme, allowing a full interaction of CO2 between the surface and the atmosphere. Statistical scores show a good representation of the Urban Heat Island (UHI) and urban-rural contrasts. Boundary layer heights (BLH) at urban, sub-urban and rural sites are well captured, especially the onset time of the BLH increase and its growth rate in the morning, that are essential for tall tower CO2 observatories. Only nocturnal BLH at sub-urban sites are slightly underestimated a few nights, with a bias less than 50 m. At Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the Atmospheric Boundary Layer (ABL) growth reaches the measurement height. The timing of the CO2 cycle is well captured by the model, with only small biases on CO2 concentrations, mainly linked to the misrepresentation of anthropogenic emissions, as the Eiffel site is at the heart of trafic emission sources. At sub-urban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a very strong spatio-temporal variability. The CO2 cycle at these sites is generally well reproduced by the model, even if some biases on the nocturnal maxima appear in the Paris plume parly due to small errors on the vertical transport, or in the vicinity of airports due to small errors on the horizontal transport (wind direction). A sensitivity test without urban parameterisation removes UHI and underpredicts nighttime BLH over urban and sub-urban sites, leading to large overestimation of nocturnal CO2 concentration at the sub-urban sites. The agreement of daytime and nighttime BLH and CO2 predictions of the reference simulation over Paris agglomeration demonstrates the potential of using the meso-scale system on urban and sub-urban area in the context of inverse modelling.

scholarly journals Polychaetes associated with the sciaphilic alga community in the northern Aegean Sea: spatial and temporal variability

2004 ◽  
Vol 58 (3) ◽  
pp. 168-182 ◽  
Author(s):  
C. Antoniadou ◽  
A. Nicolaidou ◽  
C. Chintiroglou
Keyword(s):  
Temporal Variability ◽  
Aegean Sea ◽  
Spatial And Temporal Variability ◽  
Northern Aegean Sea
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