Journal article
Sense size‐dependent dust loading and emission from space using reflected solar and infrared spectral measurements: An observation system simulation experiment
Journal of geophysical research. Atmospheres, Vol.122(15), pp.8233-8254
08/16/2017
DOI: 10.1002/2017JD026677
Abstract
The Climate Absolute Radiance and Refractivity Observatory (CLARREO) satellite mission observes hyperspectral Earth reflected solar (RS) and emitted infrared radiance (IR). Such measurements span an additional dimension on spectrally dependent scattering and absorption of dust, the critical signals for particle size. Through a suite of observation system simulation experiments (OSSEs), this study assesses the capability of CLARREO's measurements for recovering size‐dependent dust emissions in GEOS‐Chem chemistry transport model (CTM). To this end, another CTM (Flow‐following finite‐volume Icosahedral Model‐Chem, or FIM‐Chem) is used for the nature run to simulate CLARREO spectral radiances. The spectral signals are then used for analyzing the sensitivities and error characteristics of dust optical depth (DOD) under three observations scenarios (IR only, RS only, and combined IR and RS) using an optimal estimation technique. Next, these synthetic data are assimilated into GEOS‐Chem adjoint model to constrain dust emissions of four particle sizes with radii from 0.1 μm to 6.0 μm. The OSSEs results indicate (1) the IR spectra are most sensitive to dust of the third size bin (1.8–3.0 μm) and least sensitive to the smallest bin (0.1–1.0 μm); (2) the RS spectra are most sensitive to dust of the smallest size bin and the sensitivity decreases as dust size increases; (3) combining IR and RS spectra can fully characterize DOD across all sizes, providing the best constraints for size‐resolved dust emissions; and (4) CLARREO data fail to constrain the spatial distribution of dust sources due to its narrow swath and joint observations from CLARREO‐calibrated sensors with wide swath are desirable.
Key Points
OSSEs are conducted to evaluate the value of shortwave and IR spectra for characterizing size‐dependent dust loading and sources
Shortwave or infrared spectra alone lack information for the entire size range of dust aerosols
Combining shortwave and infrared spectra yields complementary constraints for size‐dependent dust loading and emissions
Plain Language Summary
Wind‐blown dust particles have a wide range of sizes. This study examines the potential of using measurements in the solar and infrared spectrum from space to characterize and derive the loading and emission of these dust particles in different sizes. The study is important because the climate effect of dust is very uncertain. The study shows that the future satellite missions that measure the solar and infrared spectrum at the same time with high spectral resolution can be used to quantify dust emissions in different sizes and thereby helping to reduce uncertainties in climate predictions.
Details
- Title: Subtitle
- Sense size‐dependent dust loading and emission from space using reflected solar and infrared spectral measurements: An observation system simulation experiment
- Creators
- Xiaoguang Xu - University of IowaJun Wang - University of IowaYi Wang - University of IowaDaven K Henze - University of ColoradoLi Zhang - NOAAGeorg A Grell - NOAAStuart A McKeen - NOAABruce A Wielicki - NASA Langley Research Center
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Atmospheres, Vol.122(15), pp.8233-8254
- DOI
- 10.1002/2017JD026677
- ISSN
- 2169-897X
- eISSN
- 2169-8996
- Number of pages
- 22
- Grant note
- National Aeronautics and Space Administration (NNX17AF78G)
- Language
- English
- Date published
- 08/16/2017
- Academic Unit
- Physics and Astronomy; Electrical and Computer Engineering; Chemical and Biochemical Engineering; Iowa Technology Institute; Civil and Environmental Engineering
- Record Identifier
- 9984104909202771
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