Monitoring the Antarctic ozone layer: MAR Project Web

Ponencia presentada en: 3ª Asamblea Hispano Portuguesa de Geodesia y Geofisica, celebrada en Valencia en 2002The Instituto Nacional de Técnica Aeroespacial (INTA) and the Instituto Nacional de Meteorología (INM) manage a joint project named MAR (Measurement of Antarctic Radiance for monitoring the ozone layer) devoted to analyse and characterise the physical-chemical mechanisms related with the ozone layer destruction over the Antarctic region. The web page of the MAR project is presented in this work. This web page shows all the information obtained from the different instruments of the joint INTA-INM Antarctic Network. The MAR’s web page provides also a quasi-real time description of the O3 and NO2 content over this region, the meteorological parameters that modulates the daily variations observed on these compounds, and the ultraviolet radiation measured at the three stations of this Antarctic network

A 10-year characterization of the Saharan Air Layer lidar ratio in the subtropical North Atlantic

Particle extinction-to-backscatter ratio (lidar ratio) is a key parameter for a correct interpretation of elastic lidar measurements. Of particular importance is its determination for Saharan Air Layer mineral dust transported into the free troposphere over the North Atlantic region. The location of the two sun photometer stations managed by the Izaña Atmospheric Research Centre (IARC) on the island of Tenerife, and a decade of available micropulse lidar (MPL) data allows us to determine the lidar ratio under almost pure dust conditions. This result can be considered representative of the Saharan dust transported westward over the North Atlantic in the subtropical belt. Three different methods to calculate the lidar ratio have been used in this work: (1) using the inversion of sky radiance measurements from a sun/sky photometer installed at the Izaña Observatory (2373ma.s.l.) in free troposphere conditions; (2) the One-Layer method, a joint determination using a micro-pulse lidar sited at Santa Cruz de Tenerife sea-level station and photometric information considering a one layer of aerosol characterized by a single lidar ratio; (3) the Two-Layer method, a joint determination using the micro-pulse lidar and photometric information considering two layers of aerosol with two different lidar ratios. The One-Layer method uses data from a co-located photometer only at Santa Cruz de Tenerife, while the Two-Layer conceptual approach incorporates photometric information at two heights from the observatories of Izaña and Santa Cruz de Tenerife. The almost pure dust lidar ratio retrieval from the sun/sky photometer and from the Two-Layer method give similar results, with lidar ratios at 523nm of 49±6 sr and 50±11sr, respectively. These values obtained from a decade of data records are coincident with other studies in the literature reporting campaigns in the subtropical North Atlantic region. This result shows that the Two-Layer method is an improved conceptual approach compared to the single layer approach, that matches well the real lower troposphere structure. The Two-layer method is able to retrieve reliable lidar ratios and therefore aerosol extinction profiles, despite the inherent limitations of the elastic lidar technique. A lack of correlation between lidar ratio and Ångström exponent (α) indicates that the dust lidar ratio can be considered independent of dust size distribution in this region. This finding suggests that dust is, in most of atmospheric conditions, the predominant aerosol in the North Atlantic free troposphere.This work has been developed within the framework of the activities of the World Meteorological Organization (WMO) Commission for Instruments and Methods of Observations (CIMO) Izaña test bed for aerosols and water vapour remote sensing instruments. AERONET Sun photometers at Izaña have been calibrated within the AERONET Europe TNA, supported by the European Union’s Horizon 2020 research and innovation program under grant agreement no. 654109 (ACTRIS-2). The authors also acknowledge the AERONET team for their support, the Juan de la Cierva postdoctoral fellowship (JCI-2010-06097) from the Spanish Ministry of Science and Innovation, as well as the AMISOC proyect, CGL2011-24891, from the Spanish Plan for Research, Development and Innovation, which has partially supported the maintenance of the lidar at Santa Cruz de Tenerife. Our colleague Celia Milford improved the English of this paper

Incrementos esporádicos de NO2 en la alta troposfera subtropical asociados a células de tormenta

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)Los óxidos de nitrógeno (NOx) juegan un papel determinante en química de la troposfera catalizando las reacciones de formación de ozono y generando radicales hidroxilo que indirectamente reducen el contenido atmosférico de CO, CH4 y CFCs. A pesar de ello, existe una incertidumbre considerable respecto a la contribución relativa de las distintas fuentes que los producen. Entre ellas, la aportación de los rayos es la mas incierta, en parte porque no se conoce cual es exactamente la actividad eléctrica global, pero también, porque la producción neta en cada rayo individual es difícil de medir

Correction and validation of total ozone data series from an antarctic multichannel filter radiometer solar UV network

Póster elaborado para la 27th General Assembly of the European Geophysical Society celebrada en Niza los días 21-26 de abril de 2002The MAR Project is financed by the National R+D Plan of the Ministry of Science and Technology (National Research Program at the Antarctica) under contract REN2000-0245-C02-2

The NILU-UV6 multichannel moderate bandwidth filter radiometer in the MAR project’s Antarctic network

Ponencia presentada en: 3ª Asamblea Hispano Portuguesa de Geodesia y Geofisica, celebrada en Valencia en 2002During the last years multichannel moderate bandwidth filter instruments have been used for UV radiation measurement and the reconstruction of the solar spectra. These instruments are now part of several UV and ozone monitoring networks, due to its easy management, low maintenance, robustness and high efficiency. In this work the characteristics, the algorithms for different products calculation, and the quality control and quality assurance system of the multichannel filter radiometer NILU-UV6 are presented. This instrument measures at five UV channels (305, 312, 320, 340 and 380 nm) and PAR (400-700 nm) channel. A radiative transfer model is used to calculate the total ozone content, clouds transmitance and the biologically effective UV doses. The preliminary results obtained by the NILU-UV6 instruments of the MAR project (Measurement of Antarctic radiance for monitoring the ozone layer) Antarctic network, managed by the Instituto Nacional de Meteorología (INM) and the Instituto Nacional de Técnica Aeroespacial (INTA), are also shown and discussed

Relationship between total ozone and UV dose rate provided by the NILU-UV6 multichannel radiometer network at the Antarctic region

Póster elaborado para el Sixth European Symposium on Stratospheric Ozone celebrado en Göteborg, Suecia, los días 2-6 de septiembre de 2002The MAR Project is financed by the National R+D Plan of the Ministry of Science and Technology (National Research Program at the Antarctica) under contract REN2000-0245-C02-02

NO2 VCD Stratospheric trends Hemispheric and latitudinal dependence

Presentación realizada para el 7th International DOAS Workshop celebrado en Bruselas los días 6-8 de julio de 2015Twenty years of stratospheric NO2 VCD data from ground-based zenith DOAS instruments have been used for trend analysis. Spectrometers either NDACC qualified or under evaluation cover Subtropical latitudes in Northern Hemisphere (Izaña, 28ºN), and Southern Antarctic (Marambio, 64ºS) and SubAntarctic (Ushuaia, 55ºS) regions. The multiple linear regression method includes annual, semiannual, quarterly, solar activity cycle, stratospheric aerosols, QBO and NAO proxies. The instruments settings follow the NDACC recommendations for NO2 measurements and the same AMF code. Results show a mean am/pm positive trend of + 7.9% at the 99% confidence level in the Northern Hemisphere station whereas the trends are negative in the Southern Hemisphere ones (-9.8% Ushuaia, -14.9% Marambio). From comparison with FTIR data, it is estimated that the changes are restricted to the lower stratosphere (15-30km) suggesting a dynamic origin of the trend. MIPAS NOy on a global scale shows a similar feature with a redistribution of the nitrogen family within the lower stratosphere

NO2 climatology in the northern subtropical region: diurnal, seasonal and interannual variability

Daily NO2 vertical column density (VCD) has been routinely measured by zenith sky spectroscopy at the subtropical station of Izaña (28° N, 16° W) since 1993 in the framework of the Network for the Detection of Atmospheric Composition Change (NDACC). Based on 14 years of data the first low latitude NO2 VCD climatology has been established and the main characteristics from short timescales of one day to interannual variability are presented. Instrumental descriptions and different sources of errors are described in detail. The observed diurnal cycle follows that expected by gas-phase NOx chemistry, as can be shown by the good agreement with a vertically integrated chemical box model, and is modulated by solar radiation. The seasonal evolution departs from the phase of the hours of daylight, indicating the signature of upper stratospheric temperature changes. From the data record (1993–2006) no significant long-term trends in NO2 VCD can be inferred. Comparison of the ground-based data sets with nadir-viewing satellite spectrometers shows excellent agreement for SCIAMACHY with differences between both datasets of 1.1%. GOME displays unrealistic features with the largest discrepancies during summer. The ground-based data are compared with long-term output of the SLIMCAT 3-D chemical transport model (CTM). The basic model, forced by ECMWF (ERA-40) analyses, captures the observed NO2 annual cycle but significantly underestimates the spring/summer maximum (by 12% at sunset and up to 25% at sunrise). In a model run which uses assimilation of satellite CH4 profiles to constrain the model long-lived tracers the agreement is significantly improved. This improvement in modelled column NO2 is due to better modelled NOy profiles and points to transport errors in the ECMWF ERA-40 reanalyses.Routine measurements have been possible thanks to the funding provided by the projects QUILT (EU EVK2-CT2000-0059) SCOUT-O3 (EU 505390-GOCE-CT-2004), TROMPETA (MCyT CGL2004-03669) and is on-going through GEOMON (EU FP6-2005-Global-4- 036677)