Observing ice clouds in the submillimeter spectral range: the CloudIce mission proposal for ESA's Earth Explorer 8

Buehler, Stefan A.; Defer, Éric; Evans, F.; Eliasson, Salomon; Mendrok, Jana; Eriksson, Patrick; Lee, C.; Jiménez, Carlos; Prigent, Catherine; Crewell, Susanne; Kasai, Yasuko; Bennartz, Ralf; Gasiewski, Albin J.

doi:10.5194/amt-5-1529-2012

Cited by 60 publications

(41 citation statements)

References 57 publications

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“…For particles heavier than 0.1 mg, shape variability can account for almost an order of magnitude in variability of the attenuation coefficient both at 150 and 220 GHz, an important signature for distinguishing different habits. A proper validation of these attenuation coefficients is also of crucial importance for the ice/snow passive microwave remote sensing techniques that make use of frequency channels within the G band (Buehler et al, 2012;Grecu and Olson, 2008;Skofronick-Jackson et al, 2004).…”

Section: Hydrometeor Attenuationmentioning

confidence: 99%

G band atmospheric radars: new frontiers in cloud physics

et al. 2014

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Abstract. Clouds and associated precipitation are the largest source of uncertainty in current weather and future climate simulations. Observations of the microphysical, dynamical and radiative processes that act at cloud scales are needed to improve our understanding of clouds. The rapid expansion of ground-based super-sites and the availability of continuous profiling and scanning multi-frequency radar observations at 35 and 94 GHz have significantly improved our ability to probe the internal structure of clouds in high temporal-spatial resolution, and to retrieve quantitative cloud and precipitation properties. However, there are still gaps in our ability to probe clouds due to large uncertainties in the retrievals.The present work discusses the potential of G band (frequency between 110 and 300 GHz) Doppler radars in combination with lower frequencies to further improve the retrievals of microphysical properties. Our results show that, thanks to a larger dynamic range in dual-wavelength reflectivity, dual-wavelength attenuation and dual-wavelength Doppler velocity (with respect to a Rayleigh reference), the inclusion of frequencies in the G band can significantly improve current profiling capabilities in three key areas: boundary layer clouds, cirrus and mid-level ice clouds, and precipitating snow.

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Section: Hydrometeor Attenuationmentioning

confidence: 99%

G band atmospheric radars: new frontiers in cloud physics

et al. 2014

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“…The ICI will carry channels featuring submillimeter frequencies ranging from 183 GHz up to 664 GHz with the frequencies 243 and 664 GHz featuring vertical and horizontal polarization. In addition to IWP, the ICI will also deliver the median mass equivalent sphere diameter and the median IWP altitude (Buehler et al 2012). …”

Section: Microwave Radiometers For Measurement Of Atmospheric Ice mentioning

confidence: 99%

Remote Sensing

Bühl

Alexander

Crewell

et al. 2017

Meteorological Monographs

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State-of-the-art remote sensing techniques applicable to the investigation of ice formation and evolution are described. Ground-based and spaceborne measurements with lidar, radar, and radiometric techniques are discussed together with a global view on past and ongoing remote sensing measurement campaigns concerned with the study of ice formation and evolution. This chapter has the intention of a literature study and should illustrate the major efforts that are currently taken in the field of remote sensing of atmospheric ice. Since other chapters of this monograph mainly focus on aircraft in situ measurements, special emphasis is put on active remote sensing instruments and synergies between aircraft in situ measurements and passive remote sensing methods. The chapter concentrates on homogeneous and heterogeneous ice formation in the troposphere because this is a major topic of this monograph. Furthermore, methods that deliver direct, process-level information about ice formation are elaborated with a special emphasis on active remote sensing methods. Passive remote sensing methods are also dealt with but only in the context of synergy with aircraft in situ measurements.

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“…Measuring the IWP continues to remain a challenging task and is an important gap in the current global climate observation system. Buehler et al (2012b) and Holl et al (2014) argued that this discrepancy is one of the reasons why there are large differences in the IWP estimates in climate models. In general, the term IWP is defined for the whole integrated ice bulk mass, for example in the work of Evans et al (2012) and Holl et al (2014).…”

Section: Introductionmentioning

confidence: 99%

“…The main purpose of ICI, as indicated by its name, is to sense ice clouds. Even though the studies of Buehler et al (2012b), Buehler et al (2007), and Jiménez et al (2007) were not explicitly carried out for ICI, they provide a useful overview of the fundamentals of ICI. The International Submillimetre Airborne Radiometer (ISMAR) is an airborne radiometer that measures at several frequencies between 118 and 664 GHz of the electromagnetic spectrum.…”

Section: Introductionmentioning

confidence: 99%

Retrieval of an ice water path over the ocean from ISMAR and MARSS millimeter and submillimeter brightness temperatures

Brath¹,

Fox

Eriksson

et al. 2018

Atmos. Meas. Tech.

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Abstract. A neural-network-based retrieval method to determine the snow ice water path (SIWP), liquid water path (LWP), and integrated water vapor (IWV) from millimeter and submillimeter brightness temperatures, measured by using airborne radiometers (ISMAR and MARSS), is presented. The neural networks were trained by using atmospheric profiles from the ICON numerical weather prediction (NWP) model and by radiative transfer simulations using the Atmospheric Radiative Transfer Simulator (ARTS). The basic performance of the retrieval method was analyzed in terms of offset (bias) and the median fractional error (MFE), and the benefit of using submillimeter channels was studied in comparison to pure microwave retrievals. The retrieval is offset-free for SIWP > 0.01 kg m to 30 % at LWP = 1 kg m −2 . The MFE of IWV for IWV > 3 kg m −2 is 5 to 8 %. The SIWP retrieval strongly benefits from submillimeter channels, which reduce the MFE by a factor of 2, compared to pure microwave retrievals. The IWV and the LWP retrievals also benefit from submillimeter channels, albeit to a lesser degree. The retrieval was applied to ISMAR and MARSS brightness temperatures from FAAM flight B897 on 18 March 2015 of a precipitating frontal system west of the coast of Iceland. Considering the given uncertainties, the retrieval is in reasonable agreement with the SIWP, LWP, and IWV values simulated by the ICON NWP model for that flight. A comparison of the retrieved IWV with IWV from 12 dropsonde measurements shows an offset of 0.5 kg m −2 and an RMS difference of 0.8 kg m −2 , showing that the retrieval of IWV is highly effective even under cloudy conditions.

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Observing ice clouds in the submillimeter spectral range: the CloudIce mission proposal for ESA's Earth Explorer 8

Cited by 60 publications

References 57 publications

G band atmospheric radars: new frontiers in cloud physics

G band atmospheric radars: new frontiers in cloud physics

Remote Sensing

Retrieval of an ice water path over the ocean from ISMAR and MARSS millimeter and submillimeter brightness temperatures

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