/pdf/k-1-coupled-gcm-miroc-description-49ogopuxgb.pdf

K-1 Coupled GCM (MIROC) Description

[1] With a global aerosol transport-radiation model coupled to a general circulation model, changes in the meteorological parameters of clouds, precipitation, and temperature caused by the direct and indirect effects of aerosols are simulated, and its radiative forcing are calculated. A microphysical parameterization diagnosing the cloud droplet number concentration based on the Kohler theory is introduced into the model, which depends not only on the aerosol particle number concentration but also on the updraft velocity, size distributions, and chemical properties of each aerosol species and saturation condition of the water vapor. The simulated cloud droplet effective radius, cloud radiative forcing, and precipitation rate, which relate to the aerosol indirect effect, are in reasonable agreement with satellite observations. The model results indicate that a decrease in the cloud droplet effective radius by anthropogenic aerosols occurs globally, while changes in the cloud water and precipitation are strongly affected by a variation of the dynamical hydrological cycle with a temperature change by the aerosol direct and first indirect effects rather than the second indirect effect itself. However, the cloud water can increase and the precipitation can simultaneously decrease in regions where a large amount of anthropogenic aerosols and cloud water exist, which is a strong signal of the second indirect effect. The global mean radiative forcings of the direct and indirect effects at the tropopause by anthropogenic aerosols are calculated to be −0.1 and −0.9 W m−2, respectively. It is suggested that aerosol particles approximately reduce 40% of the increase in the surface air temperature by anthropogenic greenhouse gases on the global mean.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2004JD005029

Simulation of climate response to aerosol direct and indirect effects with aerosol transport‐radiation model

Global distributions of the aerosol optical thickness, Angstrom exponent, and single-scattering albedo are simulated using an aerosol transport model coupled with an atmospheric general circulation model. All the main tropospheric aerosols are treated, that is, carbonaceous (organic and black carbons), sulfate, soil dust, and sea salt aerosols. The simulated total aerosol optical thickness, Angstrom exponent, and single-scattering albedo for mixtures of four aerosol species are compared with observed values from both optical ground-based measurements and satellite remote sensing retrievals at dozens of locations including seasonal variations. The mean difference between the simulation and observations is found to be less than 30% for the optical thickness and less than 0.05 for the single-scattering albedo in most regions. The simulated single-scattering albedo over the Saharan region is, however, substantially smaller than the observation, though the standard optical constant of soil dust is used in this study. The radiative forcing by the direct effect of the main tropospheric aerosols is then estimated. The global annual mean values of the total direct radiative forcing of anthropogenic carbonaceous plus sulfate aerosols are calculated to be 20.19 and 20.75 W m22 under whole-sky and clear-sky conditions at the tropopause, respectively.

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442(2002)015%3C0333%3ASSAARF%3E2.0.CO;2

Single-Scattering Albedo and Radiative Forcing of Various Aerosol Species with a Global Three-Dimensional Model

This article reviews the development of a global non-hydrostatic model, focusing on the pioneering research of the Non-hydrostatic Icosahedral Atmospheric Model (NICAM). Very high resolution global atmospheric circulation simulations with horizontal mesh spacing of approximately O (km) were conducted using recently developed supercomputers. These types of simulations were conducted with a specifically designed atmospheric global model based on a quasi-uniform grid mesh structure and a non-hydrostatic equation system. This review describes the development of each dynamical and physical component of NICAM, the assimilation strategy and its related models, and provides a scientific overview of NICAM studies conducted to date.

https://link.springer.com/content/pdf/10.1186%2Fs40645-014-0018-1.pdf

The Non-hydrostatic Icosahedral Atmospheric Model: description and development

We present an overview of state-of-the-art chemistry–climate and chemistry transport models that are used within phase 1 of the Chemistry–Climate Model Initia- tive (CCMI-1). The CCMI aims to conduct a detailed evalua- tion of participating models using process-oriented diagnos- tics derived from observations in order to gain confidence in the models’ projections of the stratospheric ozone layer, tro- pospheric composition, air quality, where applicable global climate change, and the interactions between them. Interpre- tation of these diagnostics requires detailed knowledge of the radiative, chemical, dynamical, and physical processes incor- porated in the models. Also an understanding of the degree to which CCMI-1 recommendations for simulations have been followed is necessary to understand model responses to an- thropogenic and natural forcing and also to explain inter- model differences. This becomes even more important given the ongoing development and the ever-growing complexity of these models. This paper also provides an overview of the available CCMI-1 simulations with the aim of informing CCMI data users.

/pdf/review-of-the-global-models-used-within-phase-1-of-the-3qz1w58fo6.pdf

Review of the global models used within phase 1 of the Chemistry–Climate Model Initiative (CCMI)

A new radiation scheme has been developed for dynamic
general-circulation modeling An automatic determination of
k-distribution parameters and a treatment of
solar–terrestrial radiation interacting with gaseous and particulate
matter are incorporated into the scheme by a technique that combines
discrete ordinate and matrix operator methods An accelerated
scheme for cloud overlap is developed and tested The resultant
accuracy of the scheme is ±05 K/day to a 70-km height in clear sky
better than that of the line-by-line calculation method

Modeling of the radiative process in an atmospheric general circulation model

The imager that observes the ground surface with high spatial resolution from geostationary orbit has been studied. To obtain image data with high ground sampling distance (GSD) from a geostationary orbit, an extremely large-diameter and long-focal-length telescope is required. In order to realize this imager, we plan to adopt a synthetic aperture type reflection optical telescope (Korsch type) in which the primary mirror is composed of six segmented mirrors. The diameter of the synthesized aperture telescope is approximately 3.6m, and the focal length is approximately 30 m. Prior to the development of the actual imager, we have been producing a full-scale prototype of the segmented mirror that constitutes the primary mirror and its supporting structure. The aperture shape of the prototype segmented mirror is hexagonal, and its diagonal length is approximately 1.35 m. The supporting structure of the prototype segmented mirror incorporates a mechanism (6-axes adjustment mechanism) for adjusting the alignment of the segmented mirror with six degrees of freedom. A mechanism for adjusting the curvature of the segmented mirror (curvature adjustment mechanism) was also incorporated. In this paper, the design, the manufacturing, and the testing status of this prototype are described.

/pdf/experimental-study-of-3-6-meter-segmented-aperture-telescope-2j9o81p9iq.pdf

Experimental study of 3.6-meter segmented-aperture telescope for geostationary Earth observation satellite

MOLI( M ulti-footprint O bservation L idar and I mager) Mission for globally observing forest canopy height and forest structural characteristics from ISS(Internatinal Space Station)-JEM(Japanese Experimental Module)

Earth observation satellite with a large mirror telescope has been studied in Japan Aerospace Exploration Agency to offer a fine ground sampling distance from geostationary orbit. Our latest optical design has a 3.6-m primary mirror and thus aims to obtain a ground sampling distance of sub-10 m from an altitude of 36,000 km at visible wavelengths. To achieve diffraction-limited performance in such optics on orbit, the telescope equips with not only actuators to control primary and secondary mirrors but also a deformable mirror (DM) at the exit pupil plane for the fine phasing. For on-orbit wavefront correction with a deformable mirror, a wavefront sensorless image-based aberration correction scheme is advantageous from the viewpoint of severely limited hardware resources in satellites. Phase diversity (PD) and stochastic parallel gradient descent (SPGD) optimization are known for promising image-based approaches. The former is model-based and thus the estimation accuracy of wavefront aberration significantly depends on the model accuracy, while the other requires many measurements to compensate for large aberration. To alleviate these issues, we propose sequential use of PD and SPGD optimization to efficiently reduce wavefront correction. We first developed an optical testbed with an incoherent light source, a MEMS DM, and extended image targets, and then a wavefront correction experiment was carried out. As a result, the proposed method successfully achieved diffraction-limited imaging performance with a small number of measurements. We will also discuss the image dependence of the wavefront correction performance. 

Efficient image-based wavefront correction using phase diversity and SPGD optimization for high-resolution optical remote sensing (Conference Presentation)

Toshiyoshi Kimura

Papers

Modeling of the radiative process in an atmospheric general circulation model

Experimental study of 3.6-meter segmented-aperture telescope for geostationary Earth observation satellite

MOLI( M ulti-footprint O bservation L idar and I mager) Mission for globally observing forest canopy height and forest structural characteristics from ISS(Internatinal Space Station)-JEM(Japanese Experimental Module)

Efficient image-based wavefront correction using phase diversity and SPGD optimization for high-resolution optical remote sensing (Conference Presentation)