The broadband radiometer on the EarthCARE spacecraft

Wallace, Kotska; Wright, Nick; Spilling, David; Ward, Kim; Caldwell, M.

doi:10.1117/12.825837

Cited by 9 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, accurate measurement of humidity and cloud properties during the polar night is difficult (Cimini et al, 2009;Eastman and Warren, 2010;Blanchard et al, 2014). For instance, decadal cloud cover trends are uncertain and the negative trend observed by Wang (2003) Q. Libois et al: A far infrared radiometer to study ice clouds using satellite data was not confirmed by surface observation reported by Eastman and Warren (2010). The recent deployment of satellites dedicated to clouds remote sensing, e.g., CALIPSO (Winker et al, 2003) and CloudSat (Stephens et al, 2002), has nevertheless filled a gap in clouds' observations at high latitudes (Delanoë and Hogan, 2010).…”

Section: Introductionmentioning

confidence: 99%

A microbolometer-based far infrared radiometer to study thin ice clouds in the Arctic

Libois¹,

Proulx

Ivanescu³

et al. 2016

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. A far infrared radiometer (FIRR) dedicated to measuring radiation emitted by clear and cloudy atmospheres was developed in the framework of the Thin Ice Clouds in Far InfraRed Experiment (TICFIRE) technology demonstration satellite project. The FIRR detector is an array of 80 × 60 uncooled microbolometers coated with gold black to enhance the absorptivity and responsivity. A filter wheel is used to select atmospheric radiation in nine spectral bands ranging from 8 to 50 µm. Calibrated radiances are obtained using two well-calibrated blackbodies. Images are acquired at a frame rate of 120 Hz, and temporally averaged to reduce electronic noise. A complete measurement sequence takes about 120 s. With a field of view of 6°, the FIRR is not intended to be an imager. Hence spatial average is computed over 193 illuminated pixels to increase the signal-to-noise ratio and consequently the detector resolution. This results in an improvement by a factor of 5 compared to individual pixel measurements. Another threefold increase in resolution is obtained using 193 non-illuminated pixels to remove correlated electronic noise, leading an overall resolution of approximately 0.015 W m−2 sr−1. Laboratory measurements performed on well-known targets suggest an absolute accuracy close to 0.02 W m−2 sr−1, which ensures atmospheric radiance is retrieved with an accuracy better than 1 %. Preliminary in situ experiments performed from the ground in winter and in summer on clear and cloudy atmospheres are compared to radiative transfer simulations. They point out the FIRR ability to detect clouds and changes in relative humidity of a few percent in various atmospheric conditions, paving the way for the development of new algorithms dedicated to ice cloud characterization and water vapor retrieval.

show abstract

Section: Introductionmentioning

confidence: 99%

A microbolometer-based far infrared radiometer to study thin ice clouds in the Arctic

Libois¹,

Proulx

Ivanescu³

et al. 2016

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

“…As stated formally (ESA, ), EarthCARE 's ultimate goal is to retrieve cloud and aerosol properties well enough that, when acted upon by suitable broad‐band (BB) radiative transfer models, estimated top‐of‐atmosphere (TOA) fluxes for most domains with areas ∼100 km 2 will be within ±10 W m −2 of fluxes inferred from radiances measured by its multi‐view BB radiometer (BBR). The BBR will measure nadir and two along‐track oblique views with viewing zenith angles of ∼50–55° for a common swath of width ∼10 km (Wallace et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…As stated formally (ESA, 2001(ESA, , 2006, EarthCARE's ultimate goal is to retrieve cloud and aerosol properties well enough that, when acted upon by suitable broad-band (BB) radiative transfer models, estimated top-of-atmosphere (TOA) fluxes for most domains with areas ∼100 km 2 will be within ±10 W m −2 of fluxes inferred from radiances measured by its multi-view BB radiometer (BBR). The BBR will measure nadir and two along-track oblique views with viewing zenith angles of ∼50-55 • for a common swath of width ∼10 km (Wallace et al, 2009). A notable difference between EarthCARE and its A-Train progenitors -Aqua, CloudSat and CALIPSO (Wielicki et al, 1996;Stephens et al, 2002;Winker et al, 2003) -is that, from its inception, BBR data that are not to be used for retrievals were intended to form the basis of a radiative closure experiment (cf. Oreopoulos et al, 2012), the aim of which is to assess the verisimilitude of retrieved cloud and aerosol properties (ESA, 2001).…”

Section: Introductionmentioning

confidence: 99%

Assessing the quality of active–passive satellite retrievals using broad‐band radiances

Barker

Cole

Domenech

et al. 2014

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

Included in the Earth, Clouds, Aerosols, and Radiation Explorer (EarthCARE) satellite's array of instruments is a multi-view broad-band radiometer (BBR). BBR data will facilitate a radiative closure assessment of cloud and aerosol properties inferred from data gathered by EarthCARE's other passive and active sensors. The closure assessment will consist, in part, of comparisons between BBR radiances and radiances computed by three-dimensional (3D) radiative transfer models (RTM) that act on narrow 3D domains that derive from, and include, the retrieved cross-section of cloud and aerosol properties. Assessment domains D will be ∼100 km 2 . Following a brief outline of the closure experiment, a method is proposed for estimating the likelihood of BBR radiances providing a meaningful closure assessment of cloud and aerosol properties in D. The method capitalizes on the ability of Monte Carlo RTMs to compute contributions to radiances from any constituent in any given D. While this methodology introduces some circularity into the closure test, it might, nevertheless, be tolerable, given that the method's purpose is simply to identify, and thus avoid, assessments that are likely to be fruitless or misleading. A 3000 km long stretch of A-Train satellite data was used in this initial demonstration of the proposed methodology. Only results for solar radiation are shown. All radiative quantities used here were computed by a 3D Monte Carlo RTM. A control simulation provided proxy BBR measurements. Random 'errors' were introduced into the A-Train field to produce experimental fields that roughly mimic retrievals. Experimental and control radiances were compared in mock-closure assessments. Arbitrarily assuming that a fruitful assessment requires ∼75% of a BBR radiance to result from cloud and aerosol scattering events inside D, ∼70% of the (11 km) 2 domains were flagged as reliably testable for this example.

show abstract

“…The instrument has three fixed telescopes, one for each view, each containing a broadband detector. A detailed description of the BBR instrument is provided in [1] and [2].…”

Section: Introductionmentioning

confidence: 99%

Current status of the EarthCARE BBR detectors development

et al. 2011

View full text Add to dashboard Cite

The Broadband Radiometer (BBR) is an instrument being developed for the ESA EarthCARE satellite. The BBR instrument is led by SEA in the UK with RAL responsible for the BBR optics unit (OU) while EADS Astrium is the EarthCARE prime contractor. The BBR detectors consist of three dedicated assemblies under the responsibility of INO. The detectors development started in 2008 and led to the design and implementation of a new gold black deposition facility at INO, in parallel with the preliminary and detailed design phases of the detector assemblies. As of today, two breadboard models and one engineering model have been delivered to RAL. The engineering qualification model manufacturing activities are on-going. This paper first provides an overview of the detectors assembly and principles of operation, with emphasis given to processes developed for the assembly and integration of the detectors. Detector-level qualification planning is finally discussed.

show abstract

The broadband radiometer on the EarthCARE spacecraft

Cited by 9 publications

References 0 publications

A microbolometer-based far infrared radiometer to study thin ice clouds in the Arctic

A microbolometer-based far infrared radiometer to study thin ice clouds in the Arctic

Assessing the quality of active–passive satellite retrievals using broad‐band radiances

Current status of the EarthCARE BBR detectors development

Contact Info

Product

Resources

About