CLIMCAPS observing capability for temperature, moisture, and trace gases from AIRS/AMSU and CrIS/ATMS

Abstract

Abstract. The Community Long-term Infrared Microwave Combined Atmospheric Product System (CLIMCAPS) retrieves vertical profiles of temperature, water vapor, greenhouse and pollutant gases, and cloud properties from measurements made by infrared and microwave instruments on polar-orbiting satellites. These are AIRS/AMSU on Aqua and CrIS/ATMS on Suomi NPP and NOAA20; together they span nearly 2 decades of daily observations (2002 to present) that can help characterize diurnal and seasonal atmospheric processes from different time periods or regions across the globe. While the measurements are consistent, their information content varies due to uncertainty stemming from (i) the observing system (e.g., instrument type and noise, choice of inversion method, algorithmic implementation, and assumptions) and (ii) localized conditions (e.g., presence of clouds, rate of temperature change with pressure, amount of water vapor, and surface type). CLIMCAPS quantifies, propagates, and reports all known sources of uncertainty as thoroughly as possible so that its retrieval products have value in climate science and applications. In this paper we characterize the CLIMCAPS version 2.0 system and diagnose its observing capability (ability to retrieve information accurately and consistently over time and space) for seven atmospheric variables – temperature, H2O, CO, O3, CO2, HNO3, and CH4 – from two satellite platforms, Aqua and NOAA20. We illustrate how CLIMCAPS observing capability varies spatially, from scene to scene, and latitudinally across the globe. We conclude with a discussion of how CLIMCAPS uncertainty metrics can be used in diagnosing its retrievals to promote understanding of the observing system and the atmosphere it measures.

Retrieval of Carbon Dioxide Using Cross-Track Infrared Sounder (CrIS) on S-NPP

“…NUCAPS uses the clear sky state retrieved by ATMS to simulate a clear sky top of CrIS radiation with the field of view as a reference and obtains the measured cloud-clear sky radiation. The method NUCAPS uses is the same as the one developed by the AIRS science team and employed in AIRS V6/V7 and the Community Long-Term Infrared Microwave Combined Atmospheric Product System (CLIMCAPS) [37][38][39][40]. The CCRs dataset was updated to version 2.0 on 22 May 2018.…”

Simulated Multispectral Temperature and Atmospheric Composition Retrievals for the JPL GEO-IR Sounder

“…Among many possible detectable trace gases from the extended spectral radiance measurements, we selected to examine profile retrieval characteristics for O3, CO, CH4 and CO2 for the given instrument configurations (see Table 3 for retrieval spectral ranges). (Beer, 2006;Connor et al, 2008;Deeter et al, 2009Deeter et al, , 2015George et al, 2009;Kulawik et al, 2010;Worden et al, 2010Worden et al, , 2013Clerbaux et al, 2015;Fu et al, 2016;Smith and Barnet, 2020). For a given spectral resolution instrument, the higher DOFS in retrievals for the larger GSD case for all species are due to https://doi.org/10.5194/amt-2021-290 Preprint.…”

Data Assimilation of CrIS and TROPOMI Satellite CO Concentrations and its Potential for Constraining Global OH

“…CrIS uses a Fourier Transform Spectrometer (FTS) to measure 1305 spectral channels over three infrared (IR) bands simultaneously aboard the Suomi-NPP with varying nominalspectral-resolution (NSR): long-wave IR (LWIR) at 0.625 cm -1 , mid-wave IR (MWIR) at 1.25 cm -1 , and short-wave infrared (SWIR) at 2.5 cm -1 (Smith & Barnet, 2020). Aboard the NOAA-20, "CrIS is in full-spectral-resolution (FSR) mode with all spectral bands sampled at 0.625 cm -1 " (Smith & Barnet, 2020). The CrIS User's Guide by Cao et al (2018) describes the physical components of the CrIS instrument, which includes a beamsplitter, a porchswing moving mirror, a stationary dynamic alignment mirror, a laser metrology system, and detectors.…”

“…These instruments provide and enhanced ground resolution compared to MOPITT, and view the same location on the planet at a higher frequency. For example, MOPITT's 22 km × 22 km FOV and 2-3 day global coverage (Francis et al, 2017) versus CrIS and TROPOMI's 14 km FOV and daily global coverage (D. Fu et al, 2016;Smith & Barnet, 2020). A higher resolution Joint CrIS-TROPOMI product may also in turn provide higher resolution OH distributions when assimilated into the GEOS-Chem model.…”

“…The closer the averaging kernel values are to zero, the less confidence there is in the instrument's observation and the more heavily weighted the a priori becomes (Smith & Barnet, 2020). The closer the value is to one, the more confidence there is in the instrument observation (Smith & Barnet, 2020). In other terms, the averaging kernel describes the dependence of the retrieved state vector on the true smoothed vector (Francis et al, 2017).…”