The EarthCARE mission: Mission concept and lidar instrument pre-development

Hélière, Arnaud; Lefebvre, Alain; Wehr, T.; Bézy, Jean‐Loup; Durand, Yannig

doi:10.1109/igarss.2007.4423978

Cited by 10 publications

(6 citation statements)

References 1 publication

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“…However, the conclusions will likely be valid for other spacebased radar and lidar instruments, e.g., the ATmospheric backscatter LIDar (ATLID) and the CPR onboard the Earth-CARE mission (Hélière et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Cloud vertical distribution from combined surface and space radar–lidar observations at two Arctic atmospheric observatories

Liu¹,

Shupe

Wang

et al. 2017

Atmos. Chem. Phys.

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Abstract. Detailed and accurate vertical distributions of cloud properties (such as cloud fraction, cloud phase, and cloud water content) and their changes are essential to accurately calculate the surface radiative flux and to depict the mean climate state. Surface and space-based active sensors including radar and lidar are ideal to provide this information because of their superior capability to detect clouds and retrieve cloud microphysical properties. In this study, we compare the annual cycles of cloud property vertical distributions from space-based active sensors and surface-based active sensors at two Arctic atmospheric observatories, Barrow and Eureka. Based on the comparisons, we identify the sensors' respective strengths and limitations, and develop a blended cloud property vertical distribution by combining both sets of observations. Results show that surface-based observations offer a more complete cloud property vertical distribution from the surface up to 11 km above mean sea level (a.m.s.l.) with limitations in the middle and high altitudes; the annual mean total cloud fraction from space-based observations shows 25-40 % fewer clouds below 0.5 km than from surface-based observations, and space-based observations also show much fewer ice clouds and mixed-phase clouds, and slightly more liquid clouds, from the surface to 1 km. In general, space-based observations show comparable cloud fractions between 1 and 2 km a.m.s.l., and larger cloud fractions above 2 km a.m.s.l. than from surface-based observations. A blended product combines the strengths of both products to provide a more reliable annual cycle of cloud property vertical distributions from the surface to 11 km a.m.s.l. This information can be valuable for deriving an accurate surface radiative budget in the Arctic and for cloud parameterization evaluation in weather and climate models. Cloud annual cycles show similar evolutions in total cloud fraction and ice cloud fraction, and lower liquidcontaining cloud fraction at Eureka than at Barrow; the differences can be attributed to the generally colder and drier conditions at Eureka relative to Barrow.

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Section: Introductionmentioning

confidence: 99%

Cloud vertical distribution from combined surface and space radar–lidar observations at two Arctic atmospheric observatories

Liu¹,

Shupe

Wang

et al. 2017

Atmos. Chem. Phys.

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“…Previously, spaceborne cloud and precipitation radars have been launched on board the Tropical Rainfall Measurement Mission (TRMM) by the National Aeronautics and Space Administration (NASA) and the Japanese Aerospace Exploration Agency (JAXA) (Kummerow et al, 2000), on CloudSat by NASA , and on the Global Precipitation Measurement (GPM) Core Observatory by NASA and JAXA (Hou et al, 2014). Additionally, the Earth Clouds, Aerosol and Radiation Explorer (EarthCARE), which includes a cloud radar, is currently being built by the European Space Agency and JAXA (Hélière et al, 2007). Table 1 summarizes the capabilities of the radars on these satellites.…”

Section: Introductionmentioning

confidence: 99%

Performance assessment of a triple-frequency spaceborne cloud–precipitation radar concept using a global cloud-resolving model

et al. 2015

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Abstract. Multi-frequency radars offer enhanced detection of clouds and precipitation compared to single-frequency systems, and are able to make more accurate retrievals when several frequencies are available simultaneously. An evaluation of a spaceborne three-frequency Ku-/Ka-/W-band radar system is presented in this study, based on modeling radar reflectivities from the results of a global cloud-resolving model with a 875 m grid spacing. To produce the reflectivities, a scattering model has been developed for each of the hydrometeor types produced by the model, as well as for melting snow. The effects of attenuation and multiple scattering on the radar signal are modeled using a radiative transfer model, while nonuniform beam filling is reproduced with spatial averaging. The combined effects of these are then quantified both globally and in six localized case studies. Two different orbital scenarios using the same radar are compared. Overall, based on the results, it is expected that the proposed radar would detect a high-quality signal in most clouds and precipitation. The main exceptions are the thinnest clouds that are below the detection threshold of the W-band channel, and at the opposite end of the scale, heavy convective rainfall where a combination of attenuation, multiple scattering and nonuniform beam filling commonly cause significant deterioration of the signal; thus, while the latter can be generally detected, the quality of the retrievals is likely to be degraded.

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“…By virtue of accurate calibration and straightforward independent retrievals of aerosol/cloud extinction and backscatter without reliance on a priori assumptions, high spectral resolution lidars (HSRLs) [1][2][3] are increasingly being developed and deployed on aircraft [1,4] and are called for on future satellite [5]aerosol/cloud remote sensing applications.…”

Section: Introductionmentioning

confidence: 99%

Tilted pressure-tuned field-widened Michelson interferometer for high spectral resolution lidar

Liu

Hostetler

Miller

et al. 2012

Optical Sensing and Detection II

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High spectral resolution lidars (HSRLs) designed for aerosol and cloud remote sensing are increasingly being deployed on aircraft and called for on future space-based missions. The HSRL technique relies on spectral discrimination of the atmospheric backscatter signals to enable independent, unambiguous retrieval of aerosol extinction and backscatter. NASA Langley Research Center is developing a tilted pressure-tuned field-widened Michelson interferometer (FWMI) to achieve the spectral discrimination for an HSRL system. The FWMI consists of a cubic beam splitter, a solid glass arm, and a sealed air arm. The spacer that connects the air arm mirror to the main part of the interferometer is designed to minimize thermal sensitivity. The pressure of the sealed air-arm air can be accurately controlled such that the frequency of maximum interference can be tuned with great precision to the transmitted laser wavelength. In this paper, the principle of the tilted pressure-tuned FWMI for HSRL is presented. The pressure tuning rate, the tilted angle requirement and challenges in building the real instrument are discussed.

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The EarthCARE mission: Mission concept and lidar instrument pre-development

Cited by 10 publications

References 1 publication

Cloud vertical distribution from combined surface and space radar–lidar observations at two Arctic atmospheric observatories

Cloud vertical distribution from combined surface and space radar–lidar observations at two Arctic atmospheric observatories

Performance assessment of a triple-frequency spaceborne cloud–precipitation radar concept using a global cloud-resolving model

Tilted pressure-tuned field-widened Michelson interferometer for high spectral resolution lidar

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