scholarly journals NO<sub>2</sub> seasonal evolution in the North Subtropical free troposphere

2015 ◽  
Vol 15 (10) ◽  
pp. 14473-14504
Author(s):  
M. Gil-Ojeda ◽  
M. Navarro-Comas ◽  
L. Gómez-Martín ◽  
J. A. Adame ◽  
A. Saiz-Lopez ◽  
...  
Keyword(s):  
Optical Absorption Spectroscopy ◽  
High Mountain ◽  
Horizontal Line ◽  
Free Troposphere ◽  
Seasonal Evolution ◽  
The North ◽  
Measuring Period ◽  
The Impact ◽  
Pollution Events

Abstract. Three years of Multi-Axis Differential Optical Absorption Spectroscopy (MAXDOAS) measurements (2011–2013) have been used for estimating the NO2 mixing ratio along a horizontal line of sight from the high mountain Subtropical observatory of Izaña, at 2370 m a.s.l. (NDACC station, 28.3° N, 16.5° W). The method is based on horizontal path calculation from the O2–O2 collisional complex at the 477 nm absorption band which is measured simultaneously to the NO2, and is applicable under low aerosols loading conditions. The MAXDOAS technique, applied in horizontal mode in the free troposphere, minimizes the impact of the NO2 contamination resulting from the arrival of MBL airmasses from thermally forced upwelling breeze during central hours of the day. Comparisons with in-situ observations show that during most of measuring period the MAXDOAS is insensitive or very little sensitive to the upwelling breeze. Exceptions are found during pollution events under southern wind conditions. On these occasions, evidence of fast efficient and irreversible transport from the surface to the free troposphere is found. Background NO2 vmr, representative of the remote free troposphere, are in the range of 20–45 pptv. The observed seasonal evolution shows an annual wave where the peak is in phase with the solar radiation. Model simulations with the chemistry-climate CAM-Chem model are in good agreement with the NO2 measurements, and are used to further investigate the possible drivers of the NO2 seasonality observed at Izaña.

scholarly journals NO<sub>2</sub> seasonal evolution in the north subtropical free troposphere

2015 ◽  
Vol 15 (18) ◽  
pp. 10567-10579 ◽  
Author(s):  
M. Gil-Ojeda ◽  
M. Navarro-Comas ◽  
L. Gómez-Martín ◽  
J. A. Adame ◽  
A. Saiz-Lopez ◽  
...  
Keyword(s):  
Marine Boundary Layer ◽  
Optical Absorption Spectroscopy ◽  
High Mountain ◽  
Horizontal Line ◽  
Free Troposphere ◽  
Mixing Ratio ◽  
Seasonal Evolution ◽  
The North ◽  
Measuring Period ◽  
The Impact

Abstract. Three years of multi-axis differential optical absorption spectroscopy (MAXDOAS) measurements (2011–2013) have been used for estimating the NO2 mixing ratio along a horizontal line of sight from the high mountain subtropical observatory of Izaña, at 2370 m a.s.l. (NDACC station, 28.3° N, 16.5° W). The method is based on horizontal path calculation from the O2–O2 collisional complex at the 477 nm absorption band which is measured simultaneously to the NO2 column density, and is applicable under low aerosol-loading conditions. The MAXDOAS technique, applied in horizontal mode in the free troposphere, minimizes the impact of the NO2 contamination resulting from the arrival of marine boundary layer (MBL) air masses from thermally forced upwelling breeze during middle hours of the day. Comparisons with in situ observations show that during most of the measuring period, the MAXDOAS is insensitive or very slightly sensitive to the upwelling breeze. Exceptions are found for pollution events during southern wind conditions. On these occasions, evidence of fast, efficient and irreversible transport from the surface to the free troposphere is found. Background NO2 volume mixing ratio (vmr), representative of the remote free troposphere, is in the range of 20–45 pptv. The observed seasonal evolution shows an annual wave where the peak is in phase with the solar radiation. Model simulations with the chemistry–climate CAM-Chem model are in good agreement with the NO2 measurements, and are used to further investigate the possible drivers of the NO2 seasonality observed at Izaña.

scholarly journals Long-path averaged mixing ratios of O<sub>3</sub> and NO<sub>2</sub> in the free troposphere from mountain MAX-DOAS

2013 ◽  
Vol 6 (5) ◽  
pp. 8235-8267
Author(s):  
L. Gomez ◽  
M. Navarro-Comas ◽  
O. Puentedura ◽  
Y. Gonzalez ◽  
E. Cuevas ◽  
...  
Keyword(s):  
Detection Limit ◽  
Optical Absorption ◽  
Radiative Transfer Model ◽  
Optical Absorption Spectroscopy ◽  
Transfer Model ◽  
High Mountain ◽  
Free Troposphere ◽  
Air Masses ◽  
Mixing Ratios

Abstract. A new approximation is proposed to estimate O3 and NO2 mixing ratios in the Northern Subtropics Free Troposphere (FT). Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) high mountain measurements, recorded at Izaña Observatory (28°18' N, 16°29' W), are used in this work. Proposed method uses horizontal and near-zenith geometries to estimate the station level differential path. Two different methods are described. First one uses retrieved Slant Column Densities (SCD) of O4. On second method, path is estimated from LIBRADTRAN radiative transfer model for the region and season. Results show that under low aerosol loading, O3 and NO2 mixing ratios concentrations can be retrieved with moderately low errors. Obtained concentrations have been compared with in situ instrumentation on the observatory. O3 concentration in FT is found to be in the range of 40–80 ppb, approximately. NO2 is in the range of 20–30 ppt, below the detection limit of in situ instrumentation. The different air masses scanned by each instrument have been identified as a cause of discrepancy between O3 observed by MAX-DOAS and in situ.

scholarly journals Long-path averaged mixing ratios of O<sub>3</sub> and NO<sub>2</sub> in the free troposphere from mountain MAX-DOAS

2014 ◽  
Vol 7 (10) ◽  
pp. 3373-3386 ◽  
Author(s):  
L. Gomez ◽  
M. Navarro-Comas ◽  
O. Puentedura ◽  
Y. Gonzalez ◽  
E. Cuevas ◽  
...  
Keyword(s):  
Optical Absorption Spectroscopy ◽  
High Mountain ◽  
Geometrical Approach ◽  
Free Troposphere ◽  
Simple Method ◽  
Air Masses ◽  
Mixing Ratios ◽  
Horizontal Path ◽  
Low Concentrations

Abstract. A new approximation is proposed to estimate O3 and NO2 mixing ratios in the northern subtropical free troposphere (FT). The proposed method uses O4 slant column densities (SCDs) at horizontal and near-zenith geometries to estimate a station-level differential path. The modified geometrical approach (MGA) is a simple method that takes advantage of a very long horizontal path to retrieve mixing ratios in the range of a few pptv. The methodology is presented, and the possible limitations are discussed. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) high-mountain measurements recorded at the Izaña observatory (28° 18' N, 16° 29' W) are used in this study. The results show that under low aerosol loading, O3 and NO2 mixing ratios can be retrieved even at very low concentrations. The obtained mixing ratios are compared with those provided by in situ instrumentation at the observatory. The MGA reproduces the O3 mixing ratio measured by the in situ instrumentation with a difference of 28%. The different air masses scanned by each instrument are identified as a cause of the discrepancy between the O3 observed by MAX-DOAS and the in situ measurements. The NO2 is in the range of 20–40 ppt, which is below the detection limit of the in situ instrumentation, but it is in agreement with measurements from previous studies for similar conditions.

scholarly journals Marine Wind and Wave Height Trends at Different ERA-Interim Forecast Ranges

2015 ◽  
Vol 28 (2) ◽  
pp. 819-837 ◽  
Author(s):  
Ole Johan Aarnes ◽  
Saleh Abdalla ◽  
Jean-Raymond Bidlot ◽  
Øyvind Breivik
Keyword(s):  
Wind Speed ◽  
Wave Height ◽  
North Atlantic ◽  
Wave Model ◽  
Altimeter Data ◽  
The North ◽  
The Impact ◽  
Global Reanalysis ◽  
Made In

Abstract Trends in marine wind speed and significant wave height are investigated using the global reanalysis ERA-Interim over the period 1979–2012, based on monthly-mean and monthly-maximum data. Besides the traditional reanalysis, the authors include trends obtained at different forecast range, available up to 10 days ahead. Any model biases that are corrected differently over time are likely to introduce spurious trends of variable magnitude. However, at increased forecast range the model tends to relax, being less affected by assimilation. Still, there is a trade-off between removing the impact of data assimilation at longer forecast range and getting a lower level of uncertainty in the predictions at shorter forecast range. Because of the sheer amount of assimilations made in ERA-Interim, directly and indirectly affecting the data, it is difficult, if not impossible, to distinguish effects imposed by all updates. Here, special emphasis is put on the introduction of wave altimeter data in August 1991, the only type of data directly affecting the wave field. From this, it is shown that areas of higher model bias introduce quite different trends depending on forecast range, most apparent in the North Atlantic and eastern tropical Pacific. Results are compared with 23 in situ measurements, Envisat altimeter winds, and two stand-alone ECMWF operational wave model (EC-WAM) runs with and without wave altimeter assimilation. Here, the 48-h forecast is suggested to be a better candidate for trend estimates of wave height, mainly due to the step change imposed by altimeter observations. Even though wind speed seems less affected by undesirable step changes, the authors believe that the 24–48-h forecast more effectively filters out any unwanted effects.

scholarly journals The Coastal Observing System for Northern and Arctic Seas (COSYNA)

Ocean Science ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 379-410 ◽  
Author(s):  
Burkard Baschek ◽  
Friedhelm Schroeder ◽  
Holger Brix ◽  
Rolf Riethmüller ◽  
Thomas H. Badewien ◽  
...  
Keyword(s):  
Real Time ◽  
The Arctic ◽  
Arctic Seas ◽  
The Public ◽  
The North ◽  
Data Products ◽  
The North Sea ◽  
Arctic Coast ◽  
The Impact

Abstract. The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as an example of an Arctic coast that is under strong pressure due to global change.The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publicly available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public.

Aircraft measurements of nitrous acid in excess of model predictions in the boundary layer and free troposphere

2020 ◽  
Author(s):  
Benjamin Schreiner ◽  
Klaus Pfeilsticker ◽  
Flora Kluge ◽  
Meike Rotermund ◽  
Andreas Zahn ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Absorption Spectroscopy ◽  
Free Troposphere ◽  
Aerosol Composition ◽  
Transport And Transformation ◽  
Air Masses ◽  
Airborne Measurements ◽  
Photolysis Frequencies ◽  
Model Predictions

&lt;p&gt;Middle and long-term &amp;#160;photo-chemical effects of local and regional pollution are not well quantified and are an area of active study. NO&lt;sub&gt;x&lt;/sub&gt; (here defined as NO, NO&lt;sub&gt;2&lt;/sub&gt;, and HONO) is a regional pollutant, which influences atmospheric oxidation capacity and ozone formation. Airborne measurements of atmospheric trace gases from the HALO (High Altitude Long Range) aircraft, particularly of NO, NO&lt;sub&gt;2&lt;/sub&gt;, and HONO were performed as part of the EMeRGe (Effect of Megacities on the Transport and Transformation of Pollutants on the Regional to Global Scales) campaign over continental Europe and southeast Asia in July 2017 and April 2018, respectively. NO (and NO&lt;sub&gt;Y&lt;/sub&gt;), O&lt;sub&gt;3&lt;/sub&gt;, and the photolysis frequencies of NO&lt;sub&gt;2&lt;/sub&gt; and HONO were measured in-situ. NO&lt;sub&gt;2&lt;/sub&gt; and HONO were inferred from Limb measurements of the mini-DOAS (Differential Optical Absorption Spectroscopy) instrument, using the novel scaling method (H&amp;#252;neke et al., 2017). These measurements were compared with simulations of the MECO/EMAC models. In relatively polluted air-masses in the boundary layer and free troposphere, HONO measured in excess of model predictions (and previous measurements) suggests an in-situ formation and a significant source of OH as well as a pathway for re-noxification. Aerosol composition simultaneously measured &amp;#160;by the C-Tof-AMS instrument may reveal potential reaction mechanisms to explain the discrepancy.&amp;#160;&lt;/p&gt;

Global In-Situ Observations of Essential Climate and Ocean Variables by the Global Drifter Program. Applications and Impacts

2020 ◽  
Author(s):  
Luca Centurioni ◽  
Verena Hormann
Keyword(s):  
North Atlantic Ocean ◽  
Spatial Scales ◽  
Data Access ◽  
Ocean Climate ◽  
The North ◽  
Free Data ◽  
Forecast Models ◽  
In Situ Observations ◽  
The Impact

&lt;p&gt;Accurate estimates and forecasts of physical and biogeochemical processes at the air-sea interface must rely on integrated in-situ and satellite surface observations of essential Ocean/Climate Variables (EOVs /ECVs). Such observations, when sustained over appropriate temporal and spatial scales, are particularly powerful in constraining and improving the skills, impact and value of weather, ocean and climate forecast models. The calibration and validation of satellite ocean products also rely on in-situ observations, thus creating further positive high-impact applications of observing systems designed for global sustained observations of EOV and ECVs.&lt;/p&gt;&lt;p&gt;The Global Drifter Program has operated uninterrupted for several decades and constitutes a particular successful example of a network of multiparametric platforms providing observations of climate, weather and oceanographic relevance (e.g. air-pressure, sea surface temperature, ocean currents). This presentation will review the requirements of sustainability of an observing system such as the GDP (i.e. cost effectiveness, peer-review of the observing methodology and of the technology, free data access and international cooperation), will present some key metrics recently used to quantify the impact of drifter observations, and will discuss two prominent examples of GDP regional observations and the transition to operations of novel platforms, such us wind and directional wave spectra drifters, in sparsely sampled regions of the Arabian Sea and of the North Atlantic Ocean.&lt;/p&gt;

scholarly journals The Coastal Observing System for Northern and Arctic Seas (COSYNA)

2016 ◽  
Author(s):  
B. Baschek ◽  
F. Schroeder ◽  
H. Brix ◽  
R. Riethmüller ◽  
T. H. Badewien ◽  
...  
Keyword(s):  
Real Time ◽  
The Arctic ◽  
Arctic Seas ◽  
The Public ◽  
The North ◽  
Data Products ◽  
The North Sea ◽  
Arctic Coast ◽  
The Impact

Abstract. The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example for a heavily used coastal area, and Svalbard as an example of an arctic coast that is under strong pressure due to global change. The automated observing and modelling system COSYNA is designed to monitor real time conditions, provide short-term forecasts and data products, and to assess the impact of anthropogenically induced change. Observations are carried out combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publically available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public.

scholarly journals Seasonal Progression of Ground Displacement Identified with Satellite Radar Interferometry and the Impact of Unusually Warm Conditions on Permafrost at the Yamal Peninsula in 2016

2019 ◽  
Vol 11 (16) ◽  
pp. 1865 ◽  
Author(s):  
Annett Bartsch ◽  
Marina Leibman ◽  
Tazio Strozzi ◽  
Artem Khomutov ◽  
Barbara Widhalm ◽  
...  
Keyword(s):  
Active Layer ◽  
Test Site ◽  
Radar Interferometry ◽  
Yamal Peninsula ◽  
Active Layer Thickness ◽  
Degree Days ◽  
Seasonal Evolution ◽  
X Band ◽  
The Impact

Ground subsidence monitoring by Synthetic Aperture Radar interferometry (InSAR) over Arctic permafrost areas is largely limited by long revisit intervals, which can lead to signal decorrelation. Recent satellite missions such as COSMO-Skymed (X-band) and Sentinel-1 (C-band) have comparably short time intervals of a few days. We analyze dense records of COSMO-Skymed from 2013 and 2016 and of Sentinel-1 from 2016, 2017, and 2018 for the unfrozen period over central Yamal (Russia). These years were distinct in environmental conditions and 2016 in particular was unusually warm. We evaluate the InSAR-derived displacement with in situ subsidence records, active-layer thickness measurements, borehole temperature records, meteorological data, C-band scatterometer records, and a land-cover classification based on Sentinel-1 and -2 data. Our results indicate that a comparison of seasonal thaw evolution between years is feasible after accounting for the early thaw data gap in InSAR time series (as a result of snow cover) through an assessment with respect to degree-days of thawing. Average rates of subsidence agree between in situ and Sentinel-1 (corrected for viewing geometry), with 3.9 mm and 4.3 mm per 100 degree-days of thaw at the test site. X-band and C-band records agree well with each other, including seasonal evolution of subsidence. The average displacement is more than twice in magnitude at the active-layer monitoring test site in 2016 compared to the other years. We further demonstrate that InSAR displacement can not only provide information on the magnitude of ground thaw but also on soil properties through analyses of seasonal evolution in extreme years.

Bayesian inversion of gravimetric data and assessment of CO2 dissolution in the Utsira Formation

2015 ◽  
Vol 3 (2) ◽  
pp. SP1-SP10 ◽  
Author(s):  
Vera Louise Hauge ◽  
Odd Kolbjørnsen
Keyword(s):  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Gas Production ◽  
Spatial Uncertainty ◽  
Bayesian Inversion ◽  
Monitoring Methods ◽  
The North ◽  
Gravimetric Data ◽  
The Impact

Offshore gravimetric monitoring has been introduced as a complement to seismic monitoring of fields with moving fluids. The Sleipner field in the North Sea is a fully operational carbon capture and storage facility, where [Formula: see text] is injected for storage. Gravimetric measurements are one of the geophysical monitoring methods applied, and the data have been used to estimate the in situ density and dissolution of the [Formula: see text]. We defined a Bayesian inversion of gravimetric data, and we used this to analyze gravimetric data at Sleipner field. In our approach, we included spatial uncertainty in the model and performed a Bayesian analysis of the in situ [Formula: see text] density and dissolution. We also analyzed the impact of mass changes due to gas production from the Ty Formation. Our estimates were comparable with published results.

Sign in / Sign up

Export Citation Format

Share Document