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Cirrus-induced shor...
Cirrus-induced shortwave radiative effects depending on their optical and physical properties : Case studies using simulations and measurements
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- Córdoba-Jabonero, Carmen (author)
- Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Torrejón de Ardoz, 28850 Madrid, Spain
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- Gómez-Martín, Laura (author)
- Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Torrejón de Ardoz, 28850 Madrid, Spain
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- del Águila, Ana (author)
- Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Atmospheric Sounding Station “El Arenosillo”, 21130 Huelva, Spain. Present address: Remote Sensing Technology Institute, German Aerospace Center (DLR), 82234-Oberpfaffenhofen, Germany.
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- Vilaplana, José Manuel (author)
- Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Atmospheric Sounding Station “El Arenosillo”, 21130 Huelva, Spain
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- López-Cayuela, María-Ángeles (author)
- Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Torrejón de Ardoz, 28850 Madrid, Spain
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- Zorzano, María Paz (author)
- Luleå tekniska universitet,Rymdteknik,Centro de Astrobiología (CSIC-INTA), Ctra. Ajalvir, km. 4, Torrejón de Ardoz, 28850 Madrid, Spain
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Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Torrejón de Ardoz, 28850 Madrid, Spain Instituto Nacional de Técnica Aeroespacial (INTA), Atmospheric Research and Instrumentation Branch, Atmospheric Sounding Station “El Arenosillo”, 21130 Huelva, Spain Present address: Remote Sensing Technology Institute, German Aerospace Center (DLR), 82234-Oberpfaffenhofen, Germany. (creator_code:org_t)
- Elsevier, 2020
- 2020
- English.
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In: Atmospheric research. - : Elsevier. - 0169-8095 .- 1873-2895. ; 246
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
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- Cirrus (Ci) clouds play an important role in the atmospheric radiative balance, and hence in Climate Change. In this work, a polarized Micro-Pulse Lidar (P-MPL), standard NASA/Micro Pulse NETwork (MPLNET) system, deployed at the INTA/El Arenosillo station in Huelva (SW Iberian Peninsula) is used for Ci detection and characterization for the first time at this site. Three days were selected on the basis of the predominantly detected Ci clouds in dependence on their cloud optical depth (COD). Hence, three Ci cloud categories were examined at day-times for comparison with solar radiation issues: 19 cases of sub-visuals (svCi, COD: 0.01–0.03) on 1 October 2016, 7 cases of semitransparents (stCi, COD: 0.03–0.30) on 8 May 2017, and 17 cases of opaques (opCi, COD: 0.3–3.0)on 28 October 2016. Their radiative-relevant optical, macro- and micro-physical properties were retrieved. The mean COD for the svCi, stCi and opCi groups was 0.02 ± 0.01, 0.22 ± 0.08 and 0.93 ± 0.40, respectively; in overall, their lidar ratio ranged between 25 and 35 sr. Ci clouds were detected at 11–13 km height (top boundaries) with geometrical thicknesses of 1.7–2.0 km. Temperatures reported at those altitudes corresponded to lower values than the thermal threshold for homogenous ice formation. Volume linear depolarization ratios of 0.3–0.4 (and normalized backscattering ratios higher than 0.9) also confirmed Ci clouds purely composed of ice particles. Their effective radius was within the interval of 9–15 μm size, and the ice water path ranged from 0.02 (svCi) to 9.9 (opCi) g m−2. The Cirrus Cloud Radiative Effect (CCRE) was estimated using a RT model for Ci-free conditions and Ci-mode (Ci presence) scenarios. RT simulations were performed for deriving the CCRE at the top-of atmosphere (TOA) and on surface (SRF), and also the atmospheric CCRE, for the overall shortwave (SW) range and their spectral sub-intervals (UV, VIS and NIR). A good agreement was first obtained for the RT simulations as validated against solar radiation measurements under clean conditions for solar zenith angles less than 75° (differences were mainly within ±20 W m−2 and correlation coefficients close to 1). By considering all the Ci clouds, independently on their COD, the mean SW CCRE values at TOA and SRF were, respectively, −30 ± 26 and − 24 ± 19 W m−2, being the mean atmospheric CCRE of −7 ± 7 W m−2; these values are in good agreement with global annual estimates found for Ci clouds. By using linear regression analysis, a Ci-induced enhancing cooling radiative effect was observed as COD increased for all the spectral ranges, with high correlations. In particular, the SW CCRE at TOA and SRF, and the atmospheric CCRE, presented COD-dependent rates of −74 ± 4, −55 ± 5, −19 ± 2 W m−2τ−1, respectively. Additionally, increasing negative rates are found from UV to NIR for each Ci category, reflecting a higher cooling NIR contribution w.r.t. UV and VIS ranges to the SW CCRE, and being also more pronounced at the TOA w.r.t. on SRF, as expected. The contribution of the SW CCRE to the net (SW + LW) radiative balance can be also potentially relevant. Results are especially significant for space-borne photometric/radiometric instrumentation and can contribute to validation purposes of the next ESA's EarthCARE mission, whose principal scientific goal is focused on radiation-aerosol-cloud interaction research.
Subject headings
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Rymd- och flygteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Aerospace Engineering (hsv//eng)
Keyword
- Cirrus clouds
- Cloud optical depth
- Ice water path
- Micro-pulse lidar
- Shortwave radiative effects
- Atmospheric science
- Atmosfärsvetenskap
Publication and Content Type
- ref (subject category)
- art (subject category)
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