Validation of the CLARA-A3 Top-of-Atmosphere Radiative Fluxes Climate Data Record

Author(s):
Akkermans, Tom; Clerbaux, Nicolas
Publication title: Journal of Atmospheric and Oceanic Technology
2023
 | Volume: 40 | Issue: 11
2023
DOI: 10.1175/JTECH-D-23-0065.1
Abstract:
Abstract The third edition of the CM SAF Cloud, Albedo and Surface Radiation dataset from AVHRR data (CLARA-A3) contains for the first time the top-of… Abstract The third edition of the CM SAF Cloud, Albedo and Surface Radiation dataset from AVHRR data (CLARA-A3) contains for the first time the top-of-atmosphere products reflected solar flux (RSF) and outgoing longwave radiation (OLR), which are presented and validated using CERES, HIRS, and ERA5 reference data. The products feature an unprecedented resolution (0.25°) and time span (4 decades) and offer synergy and compatibility with other CLARA-A3 products. The RSF is relatively stable; its bias with respect to (w.r.t.) ERA5 remains mostly within ±2 W m−2. Deviations are predominantly caused by absence of either morning or afternoon satellite, mostly during the first decade. The radiative impact of the Pinatubo volcanic eruption is estimated at 3 W m−2. The OLR is stable w.r.t. ERA5 and HIRS, except during 1979–80. OLR regional uncertainty w.r.t. HIRS is quantified by the mean absolute bias (MAB) and correlates with observation density and time (satellite orbital configuration), which is optimal during 2002–16, with monthly and daily MAB of approximately 1.5 and 3.5 W m−2, respectively. Daily OLR uncertainty is higher (MAB +40%) during periods with only morning or only afternoon observations (1979–87). During the CERES era (2000–20), the OLR uncertainties w.r.t. CERES-EBAF, CERES-SYN, and HIRS are very similar. The RSF uncertainty achieves optimal results during 2002–16 with a monthly MAB w.r.t. CERES-EBAF of ∼2 W m−2 and a daily MAB w.r.t. CERES-SYN of ∼5 W m−2, and it is more sensitive to orbital configuration than is OLR. Overall, validation results are satisfactory for this first release of TOA flux products in the CLARA-A3 portfolio. more
Atmosphere CM-SAF Climate Data Records Validation

Validation of the IASI FORLI/Eumetsat ozone products usingsatellite (GOME-2), ground-based (Brewer-Dobson, SAOZ) andozonesonde measurements

Author(s):
Boynard, Anne; Hurtmans, Daniel; Garane, Katerina; Goutail, Florence; Hadji-Lazaro, Juliette; Koukouli, Maria Elissavet; Wespes, Catherine; Keppens, Arno; Pommereau, Jean-Pierre; Pazmino, Andrea; Balis, Dimitris; Loyola, Diego; Valks, Pieter; Coheur, Pierre-François; Clerbaux, Cathy
2018
2018
DOI: 10.5194/amt-2017-461
Abstract:
Abstract. This paper assesses the quality of IASI/Metop-A (IASI-A) and IASI/Metop-B (IASI-B) ozone (O3) products (total and partial O3 columns) retrie… Abstract. This paper assesses the quality of IASI/Metop-A (IASI-A) and IASI/Metop-B (IASI-B) ozone (O3) products (total and partial O3 columns) retrieved with the Fast Optimal Retrievals on Layers for IASI Ozone (FORLI-O3) v20151001 software for nine years (2008–2017) through an extensive inter-comparison and validation exercise using independent observations (satellite, ground-based and ozonesonde). IASI-A and IASI-B Total O3 Columns (TOCs) are generally consistent, with a global mean difference less than 0.3 % for both day- and nighttime measurements, IASI-A being slightly higher than IASI-B. A global difference less than 2.4 % is found for the tropospheric (TROPO) O3 column product (IASI-A being lower than IASI-B), which is partly due to a temporary issue related to IASI-A viewing angle in 2015. Our validation shows that IASI-A and IASI-B TOCs are consistent with GOME-2, Dobson, Brewer and SAOZ retrieved ones, with global mean differences in the range 0.1–2 % depending on the instruments. The IASI-A and ground-based TOC comparison for the period 2008–July 2017 shows good long-term stability (negative trends within 3 % decade−1). The comparison results between IASI-A and IASI-B against smoothed ozonesonde partial O3 columns vary in altitude and latitude, with maximum standard deviation for the 300–150 hPa column (20–40 %) due to strong ozone variability and a priori uncertainty. The worst agreement with the ozonesondes and with UV-vis retrieved TOC [satellite and ground] is found at the southern high latitudes. Compared to ozonesonde data, IASI-A and IASI-B O3 products overestimate the O3 abundance in the stratosphere (up to 20 % for the 150–25 hPa column) and underestimates the O3 abundance in the troposphere (within 10 % for the mid-latitudes and ~ 18 % for the tropics). Based on the period 2011–2016, non-significant drift is found for the northern hemispheric tropospheric columns while a small drift prevails for the period before 2011. more
AC-SAF Atmosphere Climate Data Records Validation

Validation of the TROPOspheric Monitoring Instrument (TROPOMI) surface UV radiation product

Author(s):
Lakkala, Kaisa; Kujanpää, Jukka; Brogniez, Colette; Henriot, Nicolas; Arola, Antti; Aun, Margit; Auriol, Frédérique; Bais, Alkiviadis F.; Bernhard, Germar; De Bock, Veerle; Catalfamo, Maxime; Deroo, Christine; Diémoz, Henri; Egli, Luca; Forestier, Jean-Baptiste; Fountoulakis, Ilias; Garane, Katerina; Garcia, Rosa Delia; Gröbner, Julian; Hassinen, Seppo; Heikkilä, Anu; Henderson, Stuart; Hülsen, Gregor; Johnsen, Bjørn; Kalakoski, Niilo; Karanikolas, Angelos; Karppinen, Tomi; Lamy, Kevin; León-Luis, Sergio F.; Lindfors, Anders V.; Metzger, Jean-Marc; Minvielle, Fanny; Muskatel, Harel B.; Portafaix, Thierry; Redondas, Alberto; Sanchez, Ricardo; Siani, Anna Maria; Svendby, Tove; Tamminen, Johanna
Publication title: Atmospheric Measurement Techniques
2020
 | Volume: 13 | Issue: 12
2020
DOI: 10.5194/amt-13-6999-2020
Abstract:
The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (S5P) satellite was launched on 13 October 2017 to provide the atmos… The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (S5P) satellite was launched on 13 October 2017 to provide the atmospheric composition for atmosphere and climate research. The S5P is a Sun-synchronous polar-orbiting satellite providing global daily coverage. The TROPOMI swath is 2600 km wide, and the ground resolution for most data products is 7.2 × 3.5 km2 (5.6 × 3.5 km2 since 6 August 2019) at nadir. The Finnish Meteorological Institute (FMI) is responsible for the development of the TROPOMI UV algorithm and the processing of the TROPOMI surface ultraviolet (UV) radiation product which includes 36 UV parameters in total. Ground-based data from 25 sites located in arctic, subarctic, temperate, equatorial and Antarctic areas were used for validation of the TROPOMI overpass irradiance at 305, 310, 324 and 380 nm, overpass erythemally weighted dose rate/UV index, and erythemally weighted daily dose for the period from 1 January 2018 to 31 August 2019. The validation results showed that for most sites 60 %–80 % of TROPOMI data was within ±20 % of ground-based data for snow-free surface conditions. The median relative differences to ground-based measurements of TROPOMI snow-free surface daily doses were within ±10 % and ±5 % at two-thirds and at half of the sites, respectively. At several sites more than 90 % of cloud-free TROPOMI data was within ±20 % of groundbased measurements. Generally median relative differences between TROPOMI data and ground-based measurements were a little biased towards negative values (i.e. satellite data < ground-based measurement), but at high latitudes where non-homogeneous topography and albedo or snow conditions occurred, the negative bias was exceptionally high: from −30 % to −65 %. Positive biases of 10 %–15 % were also found for mountainous sites due to challenging topography. The TROPOMI surface UV radiation product includes quality flags to detect increased uncertainties in the data due to heterogeneous surface albedo and rough terrain, which can be used to filter the data retrieved under challenging conditions. more
AC-SAF Atmosphere Climate Data Records Validation

Validation of tropospheric NO2 column measurements of GOME-2A and OMI using MAX-DOAS and direct sun network observations

Author(s):
Pinardi, Gaia; Van Roozendael, Michel; Hendrick, François; Theys, Nicolas; Abuhassan, Nader; Bais, Alkiviadis; Boersma, Folkert; Cede, Alexander; Chong, Jihyo; Donner, Sebastian; Drosoglou, Theano; Dzhola, Anatoly; Eskes, Henk; Frieß, Udo; Granville, José; Herman, Jay R.; Holla, Robert; Hovila, Jari; Irie, Hitoshi; Kanaya, Yugo; Karagkiozidis, Dimitris; Kouremeti, Natalia; Lambert, Jean-Christopher; Ma, Jianzhong; Peters, Enno; Piters, Ankie; Postylyakov, Oleg; Richter, Andreas; Remmers, Julia; Takashima, Hisahiro; Tiefengraber, Martin; Valks, Pieter; Vlemmix, Tim; Wagner, Thomas; Wittrock, Folkard
Publication title: Atmospheric Measurement Techniques
2020
 | Volume: 13 | Issue: 11
2020
DOI: 10.5194/amt-13-6141-2020
Abstract:
Multi-axis differential optical absorption spectroscopy (MAX-DOAS) and direct sun NO2 vertical column network data are used to investigate the accurac… Multi-axis differential optical absorption spectroscopy (MAX-DOAS) and direct sun NO2 vertical column network data are used to investigate the accuracy of tropospheric NO2 column measurements of the GOME-2 instrument on the MetOp-A satellite platform and the OMI instrument on Aura. The study is based on 23 MAX-DOAS and 16 direct sun instruments at stations distributed worldwide. A method to quantify and correct for horizontal dilution effects in heterogeneous NO2 field conditions is proposed. After systematic application of this correction to urban sites, satellite measurements are found to present smaller biases compared to ground-based reference data in almost all cases. We investigate the seasonal dependence of the validation results as well as the impact of using different approaches to select satellite ground pixels in coincidence with ground-based data. In optimal comparison conditions (satellite pixels containing the station) the median bias between satellite tropospheric NO2 column measurements and the ensemble of MAX-DOAS and direct sun measurements is found to be significant and equal to −34 % for GOME-2A and −24 % for OMI. These biases are further reduced to −24 % and −18 % respectively, after application of the dilution correction. Comparisons with the QA4ECV satellite product for both GOME-2A and OMI are also performed, showing less scatter but also a slightly larger median tropospheric NO2 column bias with respect to the ensemble of MAX-DOAS and direct sun measurements. more
AC-SAF Atmosphere Climate Data Records Validation

Validation practices for satellite-based Earth observation data across communities: EO VALIDATION

Author(s):
Loew, Alexander; Bell, William; Brocca, Luca; Bulgin, Claire E.; Burdanowitz, Jörg; Calbet, Xavier; Donner, Reik V.; Ghent, Darren; Gruber, Alexander; Kaminski, Thomas; Kinzel, Julian; Klepp, Christian; Lambert, Jean-Christopher; Schaepman-Strub, Gabriela; Schröder, Marc; Verhoelst, Tijl
Publication title: Reviews of Geophysics
2017
 | Volume: 55 | Issue: 3
2017
DOI: 10.1002/2017RG000562
Abstract:
Assessing the inherent uncertainties in satellite data products is a challenging task. Different technical approaches have been developed in the Earth… Assessing the inherent uncertainties in satellite data products is a challenging task. Different technical approaches have been developed in the Earth Observation (EO) communities to address the validation problem which results in a large variety of methods as well as terminology. This paper reviews state-of-the-art methods of satellite validation and documents their similarities and differences. First, the overall validation objectives and terminologies are specified, followed by a generic mathematical formulation of the validation problem. Metrics currently used as well as more advanced EO validation approaches are introduced thereafter. An outlook on the applicability and requirements of current EO validation approaches and targets is given. more
Application Atmosphere CM-SAF Climate Data Records

Validation of weather reanalysis datasets and geospatial and techno-economic viability and potential assessment of concentrated solar power plants

Author(s):
Ahmad, Momina; Zeeshan, Muhammad
Publication title: Energy Conversion and Management
2022
 | Volume: 256
2022
DOI: 10.1016/j.enconman.2022.115366
Abstract:
Accelerating the decarbonization of power sector requires strategic planning and multi-aspectual feasibility analysis of renewable energy systems incl… Accelerating the decarbonization of power sector requires strategic planning and multi-aspectual feasibility analysis of renewable energy systems including, but not limited to, meteorological, land-use, techno-economic and environmental parameters. In this study, at first, the suitability of reanalysis datasets of Direct Normal Irradiance, air temperature, wind speed, relative humidity and air pressure was investigated at different timescales and locations over Pakistan. High correlation (R > 0.9) and low bias is found for Surface Solar Radiation Data records – Heliosat East, after preprocessing, among radiation datasets in consideration. Likewise, Modern-Era Retrospective analysis for Research and Applications version 2 datasets of temperature and air pressure strongly correlate with ground measurements whereas wind speed and relative humidity show peculiarity. Afterwards, resource maps from long-term timeseries are developed for each of the aforementioned parameters. In the second part, spatial feasibility and Analytical Hierarchy Process based site suitability is assessed utilizing site-specific meteorological, socio-economic and environmental parameters. Moreover, multi-parametric evaluation of techno-economic potential is performed using bias-corrected datasets. For technical potential, System Advisor Model’s Physical Trough Collector model is used for exclusively selected points. Additionally, cost of water usage is introduced in estimation of Levelized Cost of Electricity besides other parameters. Cumulative power capacity potential of 10,035 GW is identified for country, with net cost estimated below 0.096 USD/kWh. Nine sites are found to have generation potential greater than 1200 TWh/year, the individual capacity to fulfil total predicted energy demand of the country for year 2030. Around 6.5% of viable regions are found to be highly suitable for plant deployment. Land cover and lack of access to transmission network act as limiting barriers in installation of concentrated solar power plants at many potential sites across the country. more
Atmosphere CM-SAF Climate Data Records Validation

Version 2 of the EUMETSAT OSI SAF and ESA CCI sea-ice concentration climate data records

Author(s):
Lavergne, Thomas; Sørensen, Atle Macdonald; Kern, Stefan; Tonboe, Rasmus; Notz, Dirk; Aaboe, Signe; Bell, Louisa; Dybkjær, Gorm; Eastwood, Steinar; Gabarro, Carolina; Heygster, Georg; Killie, Mari Anne; Brandt Kreiner, Matilde; Lavelle, John; Saldo, Roberto; Sandven, Stein; Pedersen, Leif Toudal
Publication title: The Cryosphere
2019
 | Volume: 13 | Issue: 1
2019
DOI: 10.5194/tc-13-49-2019
Abstract:
Abstract. We introduce the OSI-450, the SICCI-25km and the SICCI-50km climate data records of gridded global sea-ice concentration. These three record… Abstract. We introduce the OSI-450, the SICCI-25km and the SICCI-50km climate data records of gridded global sea-ice concentration. These three records are derived from passive microwave satellite data and offer three distinct advantages compared to existing records: first, all three records provide quantitative information on uncertainty and possibly applied filtering at every grid point and every time step. Second, they are based on dynamic tie points, which capture the time evolution of surface characteristics of the ice cover and accommodate potential calibration differences between satellite missions. Third, they are produced in the context of sustained services offering committed extension, documentation, traceability, and user support. The three records differ in the underlying satellite data (SMMR &amp; SSM/I &amp; SSMIS or AMSR-E &amp; AMSR2), in the imaging frequency channels (37 GHz and either 6 or 19 GHz), in their horizontal resolution (25 or 50 km), and in the time period they cover. We introduce the underlying algorithms and provide an evaluation. We find that all three records compare well with independent estimates of sea-ice concentration both in regions with very high sea-ice concentration and in regions with very low sea-ice concentration. We hence trust that these records will prove helpful for a better understanding of the evolution of the Earth's sea-ice cover. more
Application Climate Data Records Cryosphere Method OSI-SAF Validation

Vortex streets to the lee of Madeira in a kilometre-resolution regional climate model

Author(s):
Gao, Q.; Zeman, C.; Vergara-Temprado, J.; Lima, D.C.A.; Molnar, P.; Schär, C.
Publication title: Weather and Climate Dynamics
2023
 | Volume: 4 | Issue: 1
2023
DOI: 10.5194/wcd-4-189-2023
Abstract:
Atmospheric vortex streets are a widely studied dynamical effect of isolated mountainous islands. Observational evidence comes from case studies and s… Atmospheric vortex streets are a widely studied dynamical effect of isolated mountainous islands. Observational evidence comes from case studies and satellite imagery, but the climatology and annual cycle of vortex shedding are often poorly understood. Using the non-hydrostatic limited-area COSMO model driven by the ERA-Interim reanalysis, we conducted a 10-year-long simulation over a mesoscale domain covering the Madeira and Canary archipelagos at high spatial (grid spacing of 1 km) and temporal resolutions. Basic properties of vortex streets were analysed and validated through a 6 d long case study in the lee of Madeira Island. The simulation compares well with satellite and aerial observations and with existing literature on idealised simulations. Our results show a strong dependency of vortex shedding on local and synoptic-flow conditions, which are to a large extent governed by the location, shape and strength of the Azores high. As part of the case study, we developed a vortex identification algorithm. The algorithm is based on a set of criteria and enabled us to develop a climatology of vortex shedding from Madeira Island for the 10-year simulation period. The analysis shows a pronounced annual cycle with an increasing vortex-shedding rate from April to August and a sudden decrease in September. This cycle is consistent with mesoscale wind conditions and local inversion height patterns. © 2023 Qinggang Gao et al. more
Application Atmosphere NWP-SAF Software for CDR development
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