Water vapor retrievals from spectral direct irradiance measured with an EKO MS-711 spectroradiometer—intercomparison with other techniques

Precipitable water vapor retrievals are of major importance for assessing and understanding atmospheric radiative balance and solar radiation resources. On that basis, this study presents the first PWV values measured with a novel EKO MS-711 grating spectroradiometer from direct normal irradiance in the spectral range between 930 and 960 nm at the Izaña Observatory (IZO, Spain) between April and December 2019. The expanded uncertainty of PWV (U$_{PWV}$) was theoretically evaluated using the Monte-Carlo method, obtaining an averaged value of 0.37 ± 0.11 mm. The estimated uncertainty presents a clear dependence on PWV. For PWV ≤ 5 mm (62% of the data), the mean U$_{PWV}$ is 0.31 ± 0.07 mm, while for PWV > 5 mm (38% of the data) is 0.47 ± 0.08 mm. In addition, the EKO PWV retrievals were comprehensively compared against the PWV measurements from several reference techniques available at IZO, including meteorological radiosondes, Global Navigation Satellite System (GNSS), CIMEL-AERONET sun photometer and Fourier Transform Infrared spectrometry (FTIR). The EKO PWV values closely align with the above mentioned different techniques, providing a mean bias and standard deviation of −0.30 ± 0.89 mm, 0.02 ± 0.68 mm, −0.57 ± 0.68 mm, and 0.33 ± 0.59 mm, with respect to the RS92, GNSS, FTIR and CIMEL-AERONET, respectively. According to the theoretical analysis, MB decreases when comparing values for PWV > 5 mm, leading to a PWV MB between −0.45 mm (EKO vs. FTIR), and 0.11 mm (EKO vs. CIMEL-AERONET). These results confirm that the EKO MS-711 spectroradiometer is precise enough to provide reliable PWV data on a routine basis and, as a result, can complement existing ground-based PWV observations. The implementation of PWV measurements in a spectroradiometer increases the capabilities of these types of instruments to simultaneously obtain key parameters used in certain applications such as monitoring solar power plants performance

Mineral dust radiative forcing and efficiency at the BSRN Izaña Station

Resumen de la comunicación oral presentada en: 1st Iberian Meeting on Aerosol Science and Technology – RICTA 2013, celebrado del 1 al 3 de julio de 2013 en Évora, Portugal

Design and description of the MUSICA IASI full retrieval product

IASI (Infrared Atmospheric Sounding Interferometer) is the core instrument of the currently three Metop (Meteorological operational) satellites of EUMETSAT (European Organization for the Exploitation of Meteorological Satellites). The MUSICA IASI processing has been developed in the framework of the European Research Council project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). The processor performs an optimal estimation of the vertical distributions of water vapour (H$_{2}$O), the ratio between two water vapour isotopologues (the HDO/H$_{2}$O ratio), nitrous oxide (N$_{2}$O), methane (CH$_{4}$), and nitric acid (HNO$_{3}$) and works with IASI radiances measured under cloud-free conditions in the spectral window between 1190 and 1400 cm$^{-1}$. The retrieval of the trace gas profiles is performed on a logarithmic scale, which allows the constraint and the analytic treatment of ln [HDO]−ln [H$_{2}$O] as a proxy for the HDO/H$_{2}$O ratio. Currently, the MUSICA IASI processing has been applied to all IASI measurements available between October 2014 and June 2021 and about two billion individual retrievals have been performed

Long-term in global solar radiation at the Izaña Atmospheric Observatory from 1933-2013

Póster elaborado para el 13th BSRN Scientific Review and Workshop celebrado en Bolonia del 9-12 de septiembre de 201

Spectral aerosol radiative forcing and efficiency of the La Palma volcanic plume over the Izaña Observatory

On 19 September 2021, a volcanic eruption began on the island of La Palma (Canary Islands, Spain). The eruption has allowed the assessment of an unprecedented multidisciplinary study on the effects of the volcanic plume. This work presents the estimation of the spectral direct radiative forcing (∆F) and efficiency (∆F E f f) from solar radiation measurements at the Izaña Observatory (IZO) located on the island of Tenerife (∼140 km from the volcano). During the eruption, the IZO was affected by different types of aerosols: volcanic, Saharan mineral dust, and a mixture of volcanic and dust aerosols. Three case studies were identified using ground based (lidar) data, satellite-based (Sentinel5P Tropospheric Monitoring Instrument, TROPOMI) data, reanalysis data (Modern-Era Retrospective Analysis for Research and Applications, version 2, MERRA-2), and backward trajectories (Flexible Trajectories, FLEXTRA), and subsequently characterised in terms of optical and micro-physical properties using ground based sun-photometry measurements. Despite the ∆F of the volcanic aerosols being greater than that of the dust events (associated with the larger aerosol load present), the ∆F E f f was found to be lower. The spectral ∆F E f f values at 440 nm ranged between −1.9 and −2.6 Wm−2nm−1AOD−1 for the mineral dust and mixed volcanic and dust particles, and between −1.6 and −3.3 Wm−2nm−1AOD−1 for the volcanic aerosols, considering solar zenith angles between 30◦ and 70◦, respectively.The authors also acknowledge the support of ACTRIS, Ministerio de Ciencia e Innovación of Spain, through the projects SYNERA: PID2020-118793GA-I00 and RT2018- 097864-B-I00, and Junta de Castilla y León grant N◦. VA227P20

Reconstruction of global solar radiation time series from 1933 to 2013 at the Izaña Atmospheric Observatory

This paper presents the reconstruction of the 80-year time series of daily global solar radiation (GSR) at the subtropical high-mountain Izaña Atmospheric Observatory (IZO) located in Tenerife (The Canary Islands, Spain). For this purpose, we combine GSR estimates from sunshine duration (SD) data using the Ångström–Prescott method over the 1933/1991 period, and GSR observations directly performed by pyranometers between 1992 and 2013. Since GSR measurements have been used as a reference, a strict quality control has been applied based on principles of physical limits and comparison with LibRadtran model. By comparing with high quality GSR measurements, the precision and consistency over time of GSR estimations from SD data have been successfully documented. We obtain an overall root mean square error (RMSE) of 9.2% and an agreement between the variances of GSR estimations and GSR measurements within 92%. Nonetheless, this agreement significantly increases when the GSR estimation is done considering different daily fractions of clear sky (FCS).Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) and from the “Fondo Europeo de Desarrollo Regional” (FEDER) for projects CGL2011-23413, CGL2012-33576 and CGL2012-37505 is acknowledged

Compatibility of different measurement techniques of global solar radiation and application for long-term observations at Izaña Observatory

A 1-year intercomparison of classical and modern radiation and sunshine duration instruments has been performed at Izaña Atmospheric Observatory. We compare global solar radiation (GSR) records measured with a Kipp & Zonen CM-21 pyranometer, taken in the framework of the Baseline Surface Radiation Network, with those measured with a multifilter rotating shadowband radiometer and a bimetallic pyranometer, and with GSR estimated from sunshine duration performed with a CS sunshine recorder

Long-term recovering of global solar radiation from 1993 to 2013 at the Izaña Atmospheric Observatory [Póster]

Póster elaborado para el International Symposium CLIMA-ES 2015 celebrado en Tortosa, Spain, los días 11-13 March 2015.Solar radiation controls the energy radiative balance in the Earth and, thus, our weather and climate. For this reason, its study has been one of the main objectives of the research community during the last decades. Recently, the focus is on evaluating long-term trends of solar radiation reaching the Earth‟s surface as well as on identifying the variability driven by the climate change. Observational evidences of changes on global solar radiation (GSR) trends have already been reported at a global scale. In this context, the goal of this work is to perform a reconstruction of the GSR time series between 1933 and 2013 at the subtropical high-mountain Izaña Atmospheric Observatory (IZA) located in Tenerife (28.3°N, 16.5°W, 2373 m a.s.l., Spain). For this purpose, we combine GSR estimates from sunshine duration (SD) data using the Ångström–Prescott method over the 1933/1991 period, and GSR observations directly performed by different pyranometers between 1992 and 2013.This work was developed under the Specific Agreement of Collaboration between the Meteorological State Agency (AEMET) of Spain and the University of Valladolid. Financial supports from the Spanish Ministry of Economy and Competitiveness (MINECO) and from the “Fondo Europeo de Desarrollo Regional” (FEDER) for projects CGL2011-23413, CGL2012-33576 and CGL2012-37505 are gratefully acknowledged

Impact of instrumental line shape characterization on ozone monitoring by FTIR spectrometry

Retrieving high-precision concentrations of atmospheric trace gases from FTIR (Fourier transform infrared) spectrometry requires a precise knowledge of the instrumental performance. In this context, this paper examines the impact on the ozone (O$_{3}$) retrievals of several approaches used to characterize the instrumental line shape (ILS) function of ground-based FTIR spectrometers within NDACC (Network for the Detection of Atmospheric Composition Change). The analysis has been carried out at the subtropical Izaña Observatory (IZO, Spain) by using the 20-year time series of the high-resolution FTIR solar absorption spectra acquired between 1999 and 2018. The theoretical quality assessment and the comparison to independent O$_{3}$ observations available at IZO (Brewer O$_{3}$ total columns and electrochemical concentration cell, ECC, sondes) reveal consistent findings. The inclusion of a simultaneous retrieval of the ILS parameters in the O$_{3}$ retrieval strategy allows, on the one hand, a rough instrumental characterization to be obtained and, on the other hand, the precision of the FTIR O$_{3}$ products to be slightly improved. The improvement is of special relevance above the lower stratosphere, where the cross-interference between the O$_{3}$ vertical distribution and the instrumental performance is more significant. However, it has been found that the simultaneous ILS retrieval leads to a misinterpretation of the O$_{3}$ variations on daily and seasonal scales. Therefore, in order to ensure the independence of the O$_{3}$ retrievals and the instrumental response, the optimal approach to deal with the FTIR instrumental characterization is found to be the continuous monitoring of the ILS function by means of independent observations, such as gas cell measurements

Comparison of observed and modeled cloud-free longwave downward radiation (2010–2016) at the high mountain BSRN Izaña station

A 7-year (2010–2016) comparison study between measured and simulated longwave downward radiation (LDR) under cloud-free conditions was performed at the Izaña Atmospheric Observatory (IZO, Spain). This analysis encompasses a total of 2062 cases distributed approximately evenly between day and night. Results show an excellent agreement between Baseline Surface Radiation Network (BSRN) measurements and simulations with libRadtran V2.0.1 and MODerate resolution atmospheric TRANsmission model (MODTRAN) V6 radiative transfer models (RTMs). Mean bias (simulated - measured) of 10 mm, the observed night-time difference between models and measurements is +5Wm-2 indicating a scale change of the World Infrared Standard Group of Pyrgeometers (WISG), which serves as reference for atmospheric longwave radiation measurements. Preliminary results suggest a possible impact of dust aerosol on infrared radiation during daytime that might not be correctly parametrized by the models, resulting in a slight underestimation of the modeled LDR, of about -3Wm-2, for relatively high aerosol optical depth (AOD>0.20).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). This research has benefited from the result of the project INMENSE (funded by the Ministerio de Economía y Competividad from Spain, CGL2016-8068