http://hdl.handle.net/20.500.11765/1578 Sun, 19 Apr 2026 15:25:44 GMT 2026-04-19T15:25:44Z http://hdl.handle.net/20.500.11765/15375 Título : LIME: Lunar Irradiance Model of ESA, a new tool for the absolute radiometric calibration using the Moon Autor : Toledano, Carlos; Taylor, Sarah; Barreto Velasco, África; Adriaensen, Stefan; Berjón, Alberto; Bialek, Agnieszka; González, Ramiro; Woolliams, Emma R.; Bouvet, Marc Resumen : Absolute calibration of Earth observation sensors is key to ensuring long term stability and interoperability, essential for long term global climate records and forecasts. The Moon provides a photometrically stable calibration source, within the range of the Earth radiometric levels and is free from atmospheric interference. However, to use this ideal calibration source one must model the variation of its disk integrated irradiance resulting from changes in Sun-Earth-Moon geometries. LIME, the Lunar Irradiance Model of the European Space Agency, is a new lunar irradiance model developed from ground-based observations acquired using a lunar photometer operating from the Izaña Atmospheric Observatory and Teide Peak, located in Tenerife, Spain. Nightly top-of-atmosphere irradiance is determined using the Langley plot method and each observation is traceable to the international system of units (SI), through the photometer calibration performed at the National Physical Laboratory. Approximately 590 lunar observations acquired between March 2018 and December 2022 currently contribute to the model parameter derivation, which builds on the widely-used ROLO (Robotic Lunar Observatory) model analytical formulation. This paper presents the strategy used to derive LIME model parameters: the characterisation of the lunar photometer, the derivation of nightly top of atmosphere lunar irradiance and a description of the model parameter derivation, along with the associated metrologically-rigorous uncertainty. The model output has been compared to PROBA-V, Pleiades, Sentinel 3B as well as to the VITO implementation of the ROLO model. Initial results indicate that LIME predicts 3 %–5 % higher disk integrated lunar irradiance than the ROLO model for the visible and near-infrared channels. The model output has an expanded (k = 2) radiometric uncertainty of ∼2 % at the lunar photometer wavelengths, and it is expected that planned observations until at least 2024 further constrain the model parameters in subsequent updates. Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.11765/15375 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.11765/15374 Título : Evaluation of “on site” calibration procedures for sun-sky photometers [Discussion paper] Autor : Campanelli, Monica; Estellés Leal, Víctor; Kumar, Gaurav; Nakajima, Teruyuki; Momoi, Masahiro; Gröbner, Julian; Kazadzis, Stelios; Kouremeti, Natalia; Karanikolas, Angelos; Barreto Velasco, África; Nevas, Saulius; Schwind, Kerstin; Schneider, Philipp; Harju, Iiro; Kärhä, Petri; Diémoz, Henri; Kudo, Rei; Uchiyama, Akihiro; Yamazak, Akihiro; Iannarelli, Anna Maria; Mevi, Gabriele; Di Bernardino, Annalisa; Casadio, Stefano Resumen : To retrieve columnar aerosol properties from sun-photometers both irradiance and radiance calibration factors are needed. For the irradiance the solar calibration constant, V0, that is the instrument counts for a direct normal solar flux extrapolated to the top of the atmosphere, must be determined. The solid view angle, SVA, is the measure of the field of view of the instrument, and it is important for obtaining the Radiance from sky diffuse irradiance measurements. Each of the three sun-photometers networks considered in the present study (SKYNET, AERONET, WMO-GAW) adopts different protocols of calibration and we evaluated the performance of the on-site calibration procedures, applied to SKYNET PREDE-POM instruments, during intercomparison campaigns and laboratory calibrations held in the framework of the Metrology for Aerosol Optical Properties (MAPP) EMPIR project. The on-site calibration, performed as frequently as possible (rather monthly) to monitor change of the machine condition, allow operators to track and evaluate the calibration status on a continuous basis considerably reducing the data gaps incurred by the periodical shipments for performing centralized calibrations. The performance of the on-site calibration procedures for V0 was very good in sites with low turbidity, showing an agreement with a reference calibration between 0.5 % and 1.5 % depending on wavelengths. In the urban area the agreement decreases between 1.7 % and 2.5 %. For the SVA the difference varied from a minimum of 0.03 % to a maximum of 3.46 %. Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.11765/15374 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.11765/15373 Título : Intercomparison of long-term ground-based measurements of tropospheric and stratospheric ozone at Lauder, New Zealand (45S) Autor : Björklund, Robin; Vigouroux, Corinne; Effertz, Peter; García Rodríguez, Omaira Elena; Geddes, Alex; Hannigan, James W.; Miyagawa, Koji; Kotkamp, Michael; Langerock, Bavo; Nedoluha, Gerald; Ortega, Ivan; Petropavlovskikh, Irina; Poyraz, Deniz; Querel, Richard; Robinson, John; Shiona, Hisako; Smale, Dan; Smale, Penny; Van Malderen, Roeland; De Mazière, Martine Resumen : Long-term ground-based ozone measurements are crucial to study the recovery of stratospheric ozone as well as the trends of tropospheric ozone. This study is performed in the context of the LOTUS (Long-term Ozone Trends and Uncertainties in the Stratosphere) and TOAR-II (Tropospheric Ozone Assessment Report, phase II) initiatives. We perform an intercomparison study of total column ozone and multiple partial ozone columns between the ground-based measurements available at the Lauder station from 2000 to 2022, which are the Fourier transform infrared (FTIR) spectrometer, Dobson Umkehr, ozonesonde, lidar, and the microwave radiometer. We compare partial columns, defined to provide independent information: one tropospheric and three stratospheric columns. The intercomparison is analyzed using the median of relative differences (the bias) of FTIR with each of the other measurements, the scaled Median Absolute deviation (MADs), and a trend of these differences (measurement drift). The total column shows a bias and strong scatter well within the combined systematic and random uncertainties respectively. There is however a drift of 0.6±0.5 %/decade if we consider the full time series. In the troposphere we find a low bias of -1.9 % with the ozonesondes. No drift is found between the three instruments in the troposphere, which is good for trend studies within TOAR-II. In both the lower and upper stratosphere, we get a negative bias for all instruments with respect to FTIR (between -1.2 % and -6.8 %), but all are within the range of the systematic uncertainties. Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.11765/15373 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.11765/15358 Título : On a Class of Linear Cooperative Systems with Spatio-temporal Degenerate Potentials Autor : Álvarez Caudevilla, Pablo; Belinchón Martín, Fernando; Brandle Cerquiera, Cristina Resumen : This paper analyses a class of parabolic linear cooperative systems in a cylindrical domain with degenerate spatio-temporal potentials. In other words, potentials vanish in some non-empty connected subdomains which are disjoint and increase in size temporally. Then, the vanishing subdomains for the potentials are not cylindrical. Following a similar idea to the semiclassical analysis behaviour, but done here for parabolic problems, under these geometrical assumptions, the asymptotic behaviour of the system is ascertained when a parameter, in front of these potentials, goes to infinity. In particular, the strong convergence of the solutions of the system is obtained using energy methods and the theory associated with the Γ-convergence. Also, the exponential decay of the solutions to zero in the exterior of the subdomains where the potentials vanish is achieved. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/20.500.11765/15358 2021-01-01T00:00:00Z