Browsing by Author "Yang, Ping"

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Collaborative Research: Systematic Evaluation and Further Improvement of Present Broadband Radiative Transfer Modeling Capabilities
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; National Science Foundation
The terrestrial climate system is sensitive to the radiation budget. Thus, accurate knowledge about the solar and thermal infrared radiation in the coupled atmosphere-ocean system is critical to robust climate study. An example of this sensitivity is the suggestion that a 1% decrease in the solar constant could lead to an ice age. The effect of doubling CO2 on radiative forcing is approximately 4 Wm-2, whereas uncertainties in radiation simulations due to, for example, insufficient knowledge about the optical properties of clouds, may be larger than this value. During the 1980s and 1990s, many researchers made substantial progress in developing and improving radiative transfer schemes used in general climate models (GCMs), and various intercomparisons of GCM radiation codes were published. Since that time, significant progress has been made in light scattering computational methods, in-situ measurements and laboratory studies of the optical and microphysical properties of clouds and aerosols, gaseous absorption line parameters and the water vapor continuum absorption, optical properties of various oceanic constituents, and the efficiency of numerical schemes for solving radiative transfer equations. There is a pressing need to incorporate the aforesaid progress into radiative transfer modeling capabilities. Moreover, the ocean and atmosphere are not coupled in many existing radiative transfer models. The scattering and absorption of radiation by oceanic water, dissolved organic matter (the so-called yellow substance), and phytoplankton have an influence in heating the uppermost water layers, and consequently affect thermal and dynamic properties such as the sea surface temperature and depth of the mixed atmosphere-ocean layer. The reflection of radiation by the oceans, including the effects of a wavy air-water interface and whitecap, can also affect the spectral characteristics and magnitude of radiation and, thus, the radiative heating and cooling rates in the atmosphere. The overarching goal is to systematically evaluate and further improve current radiative transfer modeling capabilities. Intellectual Merit: The outcomes of the study will include 1) systematic quantification of the potential errors/inaccuracies of the aforesaid radiative transfer models, 2) extension of the current radiative transfer modeling capabilities to an atmosphere-ocean coupled system, 3) implementation of spectrally consistent parameterizations of ice clouds and dust aerosols, and 4) development and implementation of a computationally efficient radiative transfer solver. Broader Impacts: The research effort will improve the radiative transfer package currently used in climate models, and be a valuable contribution to the atmospheric radiative transfer and climate study communities. Furthermore, the light scattering modeling and parameterization capabilities can find potential applications in other areas such as remote sensing of dust aerosol and ice cloud properties. The associated educational pursuits will focus on mentoring a postdoc researcher, training a graduate student, and developing teaching materials. This effort will contribute to training young researchers in the discipline of radiative transfer and light scattering that is a quite unique branch of atmospheric physics. Furthermore, the integration of RRTMG into classroom teaching will directly benefit the educational program in atmospheric sciences, particularly, in hands-on experience in atmospheric radiative transfer simulation.
Development of Community Light Scattering Computational Capabilities
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; National Science Foundation
This study seeks to develop theoretical and computational methods to improve simulations of optical properties of non-spherical particles over a broad range of size parameters. Applications of the theoretical/computational work span many broad areas of physics, chemistry, and engineering; with specific importance in atmospheric and oceanic sciences, combustion science, astrophysics, bio-optics, manufacturing diagnostics and control, and many other fields. This study will train graduate students and post-doctoral scholars. After testing and optimization, this research group plans to release the computational programs as open-source codes to the research community. This study seeks to expand previous NSF-funded research to develop advanced capabilities based on the invariant imbedding T-matrix method (II-TM) for simulating the optical properties of non-spherical, inhomogeneous particles with small to moderate size parameters. This study seeks to further improve the II-TM from both theoretical and numerical perspectives. This group recently developed a preliminary version of a physical geometric optics model (PGOM) based on either an electromagnetic volume- or a surface-integral relation for large size parameters. The suite of PGOM and II-TM will represent state-of-the-art light scattering computational capabilities, with a wide range of applications in atmospheric/oceanic radiative transfer and remote sensing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Development of Ice Cloud and Snow Optical Property Models in Support of CERES Science Team
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; NASA-Langley Research Center
1. Synopsis Surface snow and ice clouds have important impacts on the earth’s radiation budget. The single-scattering properties, namely, the phase function, single-scattering albedo, and extinction efficiency, of ice crystals are fundamental to the radiative transfer and remote sensing of ice clouds and snow. Ice crystals in clouds and snow particles are extremely complicated. Their optical properties are significantly different from “equivalent” ice spheres. It is necessary to use appropriate optical properties of ice crystal and snow particles in radiative transfer simulations and remote sensing concerning ice clouds and snow. Our research group at Texas A&M University has developed unique capabilities for simulating the optical properties of ice crystals and has been leading in this specific research area. For this project, we propose, building on existing on research, to simulate the optical properties of ice/snow particles in support of the NASA CERES (Clouds and the Earth’s Radiant Energy System) Science Team. Specifically, we propose the following three major tasks: 1) Improve and validate a new ice cloud bulk radiative property model; furthermore, generate look-up tables (LUTs) in support of the cloud property retrievals by the CERES Science Team using the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Visible and Infrared Imaging Radiometer Suite (VIIRS) observations. 2) Develop a novel snow albedo model in support of the radiative transfer model used by the CERES team for flux calculations. 3) Document and deliver the optical property and LUT data; furthermore, publish the research findings in peer-reviewed scientific journals.
Improved Community Radiative Transfer Model (CRTM CRTM for Ultra-Violet (UV) and Passive Microwave Hydrometeor Simulation
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; DOC-National Oceanic and Atmospheric Administration
In support of CRTM, it is important to develop robust graupel and snowflake optical property models, which will achieve spectral consistency (i.e., the data will be spectrally consistent across from ultraviolet to microwave spectral regimes). In far-infrared to microwave regimes, the ice refractive index has dependence on temperature and is critical to remote sensing applications and radiative flux estimations. The goal of this work is to use a synergy of a suit of light-scattering modeling capabilities (specifically, the invariant-imbedding T-matrix model (II-TM) and the improved geometric optics model (IGOM)] to compute the single-scattering properties of realistic graupel and snowflake particles, and to develop the bulk single-scattering properties of these hydrometeors with various particle size distributions. We will leverage particle geometry of graupel and snowflakes with considering various ice density and hollow structures inside these hydrometeors. The proposed research effort will be directed towards answering the question: “how do realistic graupel and snowflake models improve forward radiative transfer simulations based on CRTM for remote sensing and data assimilation applications?” To address the question, requested efforts will be focused on the followings.
Optical property calculations and radiation parameterizations in support of CERES Science Team
Atmospheric Sciences; TAMU; NASA-Langley Research Center
Ice clouds and snow on the surface play a major role in the Earth–atmosphere energy budget through their interactions with shortwave and longwave radiation. The single-‐scattering properties of ice crystals are fundamental to radiative transfer simulations and remote sensing implementations concerning the microphysical and optical properties ice clouds and snow. Generally speaking, ice crystals in clouds and particles in snow on the surface are almost exclusively nonspherical particles with the single-‐scattering properties deviating substantially from the counterparts based on the “equivalent” ice spheres. Therefore, it is necessary to use appropriate optical properties of ice crystals and snow particles. In support of the CERES (Clouds and the Earth’s Radiant Energy System) Science Team, our research group at Texas A&M University has developed a two-‐habit model (THM) for ice cloud optical properties. Figure 1 shows the ice particle shape distribution assumed for the THM. The optical properties associated with the THM leads to improvements in downstream applications to satellite remote sensing. For example, Figure 2 shows the polarized reflectivities simulated based on the CERES Edition 2 and the THM optical properties in comparison with the observations made by the Polarization and Directionality of the Earth’s Reflectance (POLDER). Overall, the observed polarized reflectivity decreases with increasing scattering angle over a range of 100°–170°. The simulations based on the THM closely match with those from the observations except at the scattering angles with 100–120° because of the weak polarized side-‐scattering by the THM, whereas the simulations based on the CERES Edition 2 substantially deviate from the observations. It is obvious that THM represents a significant improvement compared the CERES Edition 2 ice cloud optical model.
Optical property calculations and radiation parameterizations in support of CERES Science Team
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; NASA-Langley Research Center
Ice clouds and snow on the surface play a major role in the Earth–atmosphere energy budget through their interactions with shortwave and longwave radiation. The single-?scattering properties of ice crystals are fundamental to radiative transfer simulations and remote sensing implementations concerning the microphysical and optical properties ice clouds and snow. Generally speaking, ice crystals in clouds and particles in snow on the surface are almost exclusively nonspherical particles with the single-?scattering properties deviating substantially from the counterparts based on the “equivalent” ice spheres. Therefore, it is necessary to use appropriate optical properties of ice crystals and snow particles. In support of the CERES (Clouds and the Earth’s Radiant Energy System) Science Team, our research group at Texas A&M University has developed a two-?habit model (THM) for ice cloud optical properties. Figure 1 shows the ice particle shape distribution assumed for the THM. The optical properties associated with the THM leads to improvements in downstream applications to satellite remote sensing. For example, Figure 2 shows the polarized reflectivities simulated based on the CERES Edition 2 and the THM optical properties in comparison with the observations made by the Polarization and Directionality of the Earth’s Reflectance (POLDER). Overall, the observed polarized reflectivity decreases with increasing scattering angle over a range of 100°–170°. The simulations based on the THM closely match with those from the observations except at the scattering angles with 100–120° because of the weak polarized side-?scattering by the THM, whereas the simulations based on the CERES Edition 2 substantially deviate from the observations. It is obvious that THM represents a significant improvement compared the CERES Edition 2 ice cloud optical model.
Quantification of the Consistency of the Choice of Ice Cloud Models in Forward Retrieval and Radiative Forcing Assessment
Atmospheric Sciences; TAMU; National Aeronautics And Space Administration
For retrievals of ice cloud microphysical and radiative properties (specifically, effective particle size and optical thickness), different science teams assume different ice particle habit models in the look‐up tables that involve forward light scattering and radiative transfer model. For example, the CERES Edition 4 ice cloud property retrieval assumes a single habit model (specifically, hexagonal ice crystals with surface roughness), the MODIS Collection 6 ice cloud property retrieval assumes roughened aggregates, and the AIRS science team adopted the MODIS Collection 5 ice model (a mixture of various ice particle habits) in the infrared regime. Recently, it is found (Leob et al. 2017) that the effect of an ice particle habit on cloud radiative forcing assessment is minimized if the same ice habit model is used for the retrieval and the radiative transfer model. This finding promotes a hypothesis (hereafter, the consistency hypothesis) that, to minimize errors, a consistent ice cloud model must be used for satellite based cloud property retrievals and the assessment of ice cloud radiative forcing. The proposed research is to comprehensively validate the consistency hypothesis using MODIS Collection 6, CERES‐MODIS Edition 4, AIRS, and NPP/VIIRS cloud retrieval products. To allow robust simulation, we will use the level‐2 retrieval products. Only the pixels collocated with CALIPSO data will be used. The CALIPSO measurements will be used to constrain cloud height. Furthermore, the MERRA reanalysis data will be used to provide atmospheric vertical profiles. The aforesaid cloud property retrieval products will be used as input for radiative transfer simulations in comparison with the CERES flux products. Furthermore, we will develop ice cloud parameterizations consistent with various satellite retrieval products for two radiative transfer models used in climate models. The purpose of developing various ice cloud parameterizations is to allow the users of cloud property retrieval products to have an appropriate parameterization in the assessment of ice cloud radiative forcing. Potential impact: the outcomes of this project will directly benefit 1) improving the accuracy of the assessment of ice cloud radiative forcing; and 2) choosing an appropriate parameterization scheme that is consistent with a specific cloud property retrieval product (e.g., MODIS Collection 6 or AIRS cloud property product) to validate climate models.
Quantification of the Consistency of the Choice of Ice Cloud Models in Forward Retrieval and Radiative Forcing Assessment
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; National Aeronautics And Space Administration
For retrievals of ice cloud microphysical and radiative properties (specifically, effective particle size and optical thickness), different science teams assume different ice particle habit models in the look-up tables that involve forward light scattering and radiative transfer model. For example, the CERES Edition 4 ice cloud property retrieval assumes a single habit model (specifically, hexagonal ice crystals with surface roughness), the MODIS Collection 6 ice cloud property retrieval assumes roughened aggregates, and the AIRS science team adopted the MODIS Collection 5 ice model (a mixture of various ice particle habits) in the infrared regime. Recently, it is found (Leob et al. 2017) that the effect of an ice particle habit on cloud radiative forcing assessment is minimized if the same ice habit model is used for the retrieval and the radiative transfer model. This finding promotes a hypothesis (hereafter, the consistency hypothesis) that, to minimize errors, a consistent ice cloud model must be used for satellite based cloud property retrievals and the assessment of ice cloud radiative forcing. The proposed research is to comprehensively validate the consistency hypothesis using MODIS Collection 6, CERES-MODIS Edition 4, AIRS, and NPP/VIIRS cloud retrieval products. To allow robust simulation, we will use the level-2 retrieval products. Only the pixels collocated with CALIPSO data will be used. The CALIPSO measurements will be used to constrain cloud height. Furthermore, the MERRA reanalysis data will be used to provide atmospheric vertical profiles. The aforesaid cloud property retrieval products will be used as input for radiative transfer simulations in comparison with the CERES flux products. Furthermore, we will develop ice cloud parameterizations consistent with various satellite retrieval products for two radiative transfer models used in climate models. The purpose of developing various ice cloud parameterizations is to allow the users of cloud property retrieval products to have an appropriate parameterization in the assessment of ice cloud radiative forcing. Potential impact: the outcomes of this project will directly benefit 1) improving the accuracy of the assessment of ice cloud radiative forcing; and 2) choosing an appropriate parameterization scheme that is consistent with a specific cloud property retrieval product (e.g., MODIS Collection 6 or AIRS cloud property product) to validate climate models.
Refinement of the MODIS Cloud Optical Product in Synergy with Continued Development of a Full Suite of EOS-SNPP Cloud Continuity Algorithm + Atmosphere Discipline Team Leads
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; NASA-Goddard Space Flight Center
Statement of work 1. Synopsis: A research proposal entitled “Refinement of the MODIS Cloud Optical Product in Synergy with Continued Development of a Full Suite of EOS-SNPP Cloud Continuity Algorithm + Atmosphere Discipline Team Leads” (Principal Investigator: Dr. Steven Platnick from NASA Goddard Space Flight Center, and several co-investigators from different institutions) has been selected for funding support. Prof. Ping Yang from Texas A&M University (TAMU) is one of the co-investigators of the aforesaid proposal. A subaward 80NSSC18K1516 (Project performance period: 01-Oct-2019 to 30-Sep-2020) has been awarded to TAMU to conduct research in support of the funded project. Our TAMU team is the long-time provider of ice particle scattering calculations and related radiative transfer code for the MODIS science team. With the present proposal, we request supplemental funding support to continue the aforesaid research. In particular, the radiative transfer modeling capabilities developed in the previous effort of grant 80NSSC18K1516 need further improvements and refinements. We believe that the outcomes of the supplemental support will contribute to NASA’s mission, particularly the MODIS Science team. 2. Description of Work: The Texas A&M University team will continue to enhance the fast radiative transfer modeling capabilities developed in the previous two years of grant 80NSSC18K1516. Listed below are the specific research tasks and deliverables during 10/1/2020-9/30/2021. 2.1. Specific Tasks: • Further improve the gas absorption parameterization model and implement it in the Aqua/Terra MODIS, VIIRS, PARASOL and GOES-16 ABI bands. • Complete the Jacobian matrix calculation capability of the radiative transfer equation solver developed via our previous effort. • Combine the gas absorption parameterization model and the aforesaid radiative solver in a seamless form. • Design a user-friendly input and output module for the aforementioned combined model, including the documentation of the computational programs
Remote Sensing of Ice Cloud Properties Using CLARREO-like Spectrally Resolved Reflected Solar and Infrared Radiances
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; National Aeronautics And Space Administration
Abstract As the science community seeks to get a better handle on the energy budget of Earth’s atmosphere, ice clouds continue to be a source of significant uncertainty. Ice cloud microphysical and optical properties (i.e. effective radius and optical depth) are among the most uncertain components in our understanding of cloud-climate forcings and feedbacks. Reduction in cloud feedback uncertainty was recommended as a most important endeavor by the decadal survey (National Academy of Sciences, 2017). The Climate Absolute Radiance and Reflectivity Observatory Pathfinder (CLARREO-PF), while not specifically designed for cloud research, will provide hyperspectral measurements of the solar reflected radiance over the range of 320 – 2300 nm. Such a complete measurement of the reflected solar spectrum provides an impressive platform to study microphysical and optical properties of ice clouds in an effort to increase information, reduce noise, and analyze spectral consistency of the retrievals. With this proposal, we seek to leverage recent advancements in ice particle radiative modeling and CLARREO-Pathfinder’s unique accuracy, spectrally resolved reflectances, and Shannon information content for retrieval of ice cloud optical depth and effective radius in order to reduce uncertainty in global distributions of cloud optical properties. Finally, using NASA’s proposed CLARREO-Infrared (CLARREO-IR) and Polar Radiant Energy in the Far-Infared Experiment (PREFIRE) as inspiration, we will investigate the expansion of our study into the far-infrared.
Remote Sensing Of Ice Cloud Properties Using High Frequency Sub-Millimeter Wave Radiometry - Student: Adam Bell
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; NASA-Washington
1. Abstract Ice clouds play a substantial role in the Earth’s climate system, particularly through their influence on the global energy budget. Fundamental ice cloud parameters for quantifying cloud radiative properties are ice water path (IWP) and ice particle effective diameter (Deff). Current General Circulation Models (GCMs) vary in their estimation of cloud IWP by as much as an order of magnitude. Imposing constraints from observations is challenging since ice mass retrievals are generally ill conditioned (i.e. less information content in observations than the solution). Sub-millimeter (sub-mm) wave radiometry is an emerging technique for characterizing cloud properties due to high sensitivity to ice cloud parameters, in particular IWP. The continued aim of this project is to develop effective retrieval techniques utilizing passive high frequency sub-millimeter (sub-mm) and thermal infrared (IR) observations to infer such ice cloud properties. A robust sub-mm climatology of ice cloud microphysical properties helps provide a more holistic understanding of ice clouds and acts as a constraint to increase model performance, but also advances one of NASA’s overarching goals in Earth Science: advance the understanding of change in the Earth’s radiation balance…that result from changes in atmospheric composition. Summarized below are the major accomplishments since the previous reporting, which relate directly to the initial and previous timeline of research. We also provide an updated timeline of research to be conducted for the remainder of this project, as well as a list of current and future conference presentations.
Research in Support of JPSS CAL/VAL
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; DOC-National Oceanic and Atmospheric Administration
In support JPSS CAI/Val effort, It Is Important to develop an optimal Ice cloud optical/radiative property forward model required for Testlns/valldatina/lmplementing retrieval alaorlthms based on JPSS observation. The aoal of this work Is to understand the Impact of the auumed Ice mlcrophyslcal model on doud property retrieval based on Infrared bands. In particular, spectral bands centered at 8.5 um, 10.4 lffl , 11 um and 12 um will be used. The proposed research effort will be directed towards answer the question: "how does the Ice model choice Impact on Ice cloud property retrieval?" To address this question, the first task Is to develop an lmpl'Olled Ice model at the afotesald four spectral bands and to Include mora scatterln& physics to Improve the products. In partlcular, research wru be conducted towards a better understandlns the usefulness of the 10.4-cm band. Furthermore, the second task Is to evaluate the performance of the fee doud model for retrievals In the tropical, mid-latitude, d polar regions.
Study of Dust Aerosol Optical and Microphysical Properties Based on Combined Spaceborne Lidar and Polarimetry Observations
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; National Aeronautics And Space Administration
Deserts around the world emit tons of dust aerosols into the atmosphere. Except for playing a role in earth’s materials cycle, dust aerosol has been found to significantly impact the earth energy budget by acting as direct and indirect radiative forcings. The complexity of dust aerosol optical and microphysical properties leads to large variety of dust aerosol radiative effect. Current radiative transfer simulation and climate modeling usually assume constant dust aerosol property because of little knowledge of its variability. To reduce the uncertainties, it is necessary to have a quantitative understanding of spatial and temporal variability of dust aerosol properties. We propose to use combined observations from spaceborne lidar and polarimeter, together with modeling capabilities to study the variability of dust aerosol optical and microphysical properties including optical thickness, absorptive ability, effective particle size, and particle nonsphericity. Lidar is able to measure the vertical profile of dust aerosol backscattering. Our preliminary findings suggest that the lidar signal is not only sensitive to dust aerosol optical thickness and nonsphericity, but also sensitive to effective particle size. However, those dust aerosol properties cannot be determined uniquely only from lidar observation due to nonsufficient a priori knowledge. Multi-channel and multi-angle polarization measurement will provide more information of particle size and optical thickness. The latest Decadal Survey report prioritizes the observations of aerosol properties and vertical profile with backscatter lidar and multi-channel and multi-angle polarimeter. The proposed study is highly relevant to NASA and is in alignment with the concept by using combined spaceborne lidar and polarimetry observations to study dust aerosol optical and microphysical property variability.
SWIRP: Compact Wave and LWIR Polarimeters for Cirrus Ice Properties
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; NASA-Goddard Space Flight Center
Perform numerical modeling simulations regarding sub millimeter and longwave infrared ice cloud microphysics and to conduct relevant analyses.
Utilizing geostationary satellite observations to develop a next generation ice cloud optical property model in support of JCSDA Community Radiative Transfer Model (CRTM) and JPSS CAL/VAL
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/202; Department of Commerce
SOW As a flagship effort of a multi-agency (NOAA, NASA, Navy and Air Force) Joint Center for Satellite Data Assimilation (JCSDA), the Community Radiative Transfer Model (CRTM) is a powerful and robust tool to facilitate the forward and adjoint radiative transfer simulations involved in satellite remote sensing programs and data assimilation efforts. Although the CRTM is a state-of-the-art radiative transfer package, ice optical property model used in CRTM is obsolete. Ice clouds are ubiquitous in the atmosphere, covering approximately 40% of the tropics and 20% of the globe. These clouds play important roles in the radiative transfer process in the earth-atmosphere coupled system. It is well known that the “equivalent-sphere” model for ice clouds produces significant errors or even misleading results. Progress in developing of more realistic nonspherical ice crystal models has been steady but slow. The existing ice cloud optical property models still suffer various shortcomings, for example, some models lead to inconsistency for applications in the solar and infrared spectral regimes, and some models lacks microphysical consistency in comparison with in situ measurements. In response to this funding opportunity, we propose to develop a next generation ice model in support of the Community Radiative Transfer Model (CRTM) and the improved modeling capability will benefit the CAL/VAL efforts in conjunction with the Joint Polar Satellite System (JPSS). We will use observations made by the Advanced Baseline Imager (ABI) aboard GOES-16 and GOES 17 with high temporal resolution to first infer the radiative and microphysical properties (specifically, optical thickness and the effective particle size) using both the solar bi-spectral technique (i.e., the Nakajima-King method) and the infrared split window technique with daytime ABI observations while only infrared technique will be used for nighttime retrieval. Furthermore, we will collocate the aforesaid retrievals with collocated CALIOP retrieval. In the proposed retrievals, an ice cloud optical property model must be used. We will test various ice cloud models. The optimal model is the one that will lead to spectral consistency between solar-band and IR-band based retrievals and consistency between passive (ABI based) and active (CALIOP based) retrievals. After an optimal ice cloud model is identified, we will implement it in CRTM. Specifically, the implementation will be conducted for the channels of Cross-track infrared Soundar (CrIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) on JPSS. This effort will support JPSS CAL/VAL effort. We call special attention to the optical ice cloud optical properties generated through the proposed project, which can be directly used to generate the forward look-up tables involved in JPSS-based cloud property retrievals in consistent with the improved CRTM so that data assimilation using CRTM and JPSS cloud products are consistent.
Utilizing geostationary satellite observations to develop a next generation ice cloud optical property model in support of JCSDA Community Radiative Transfer Model (CRTM) and JPSS CAL/VAL
Atmospheric Sciences; TAMU; Department of Commerce
As a flagship effort of a multi-agency (NOAA, NASA, Navy and Air Force) Joint Center for Satellite Data Assimilation (JCSDA), the Community Radiative Transfer Model (CRTM) is a powerful and robust tool to facilitate the forward and adjoint radiative transfer simulations involved in satellite remote sensing programs and data assimilation efforts. Although the CRTM is a state-of-the-art radiative transfer package, ice optical property model used in CRTM is obsolete. Ice clouds are ubiquitous in the atmosphere, covering approximately 40% of the tropics and 20% of the globe. These clouds play important roles in the radiative transfer process in the earth-atmosphere coupled system. It is well known that the “equivalent-sphere” model for ice clouds produces significant errors or even misleading results. Progress in developing of more realistic nonspherical ice crystal models has been steady but slow. The existing ice cloud optical property models still suffer various shortcomings, for example, some models lead to inconsistency for applications in the solar and infrared spectral regimes, and some models lacks microphysical consistency in comparison with in situ measurements. In response to this funding opportunity, we propose to develop a next generation ice model in support of the Community Radiative Transfer Model (CRTM) and the improved modeling capability will benefit the CAL/VAL efforts in conjunction with the Joint Polar Satellite System (JPSS). We will use observations made by the Advanced Baseline Imager (ABI) aboard GOES-16 and GOES 17 with high temporal resolution to first infer the radiative and microphysical properties (specifically, optical thickness and the effective particle size) using both the solar bi-spectral technique (i.e., the Nakajima-King method) and the infrared split window technique with daytime ABI observations while only infrared technique will be used for nighttime retrieval. Furthermore, we will collocate the aforesaid retrievals with collocated CALIOP retrieval. In the proposed retrievals, an ice cloud optical property model must be used. We will test various ice cloud models. The optimal model is the one that will lead to spectral consistency between solar-band and IR-band based retrievals and consistency between passive (ABI based) and active (CALIOP based) retrievals. After an optimal ice cloud model is identified, we will implement it in CRTM. Specifically, the implementation will be conducted for the channels of Cross-track infrared Soundar (CrIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) on JPSS. This effort will support JPSS CAL/VAL effort. We call special attention to the optical ice cloud optical properties generated through the proposed project, which can be directly used to generate the forward look-up tables involved in JPSS-based cloud property retrievals in consistent with the improved CRTM so that data assimilation using CRTM and JPSS cloud products are consistent.