The University of Tokyo · Environmental Science
Professor Woosub Roh's research lab specializes in cloud-system-resolving modeling and satellite-based evaluation of tropical and mid-latitude cloud systems, with a focus on improving the representation of cloud microphysics and precipitation processes. The lab develops and evaluates advanced cloud microphysics schemes using high-resolution global models such as NICAM, combined with multi-sensor satellite observations and satellite simulators. Key research directions include the quantitative evaluation of cloud phase, echo-top height, and precipitation using data from TRMM, CALIPSO, and EarthCARE, as well as the development of novel retrieval and evaluation techniques for deep convective systems. The lab also investigates the impact of model resolution and microphysical parameterizations on the simulation of cloud systems and radiative fluxes.
Figures are computed from collected data and may differ slightly.
Abstract Cloud microphysics of deep convective systems over the tropical central Pacific simulated by a cloud system–resolving model using satellite simulators are evaluated in terms of the joint histogram of cloud-top temperature and precipitation echo-top heights. A control experiment shows an underestimation of stratiform precipitation and a higher frequency of precipitating deep clouds with top heights higher than 12 km when compared with data from the Tropical Rainfall Measuring Mission. Th
Abstract The cloud and precipitation simulated by a global nonhydrostatic model with a 3.5-km horizontal resolution, the Nonhydrostatic Icosahedral Atmospheric Model (NICAM), are evaluated using the Tropical Rainfall Measuring Mission (TRMM) and a satellite simulator. A previous study by Roh and Satoh evaluated the single-moment bulk microphysics and established the modified microphysics scheme for the specific tropical open ocean using a regional version of NICAM. In this study, the authors exp
Abstract A new evaluation method for the thermodynamic phases of clouds in cloud-system-resolving models is presented using CALIPSO observations and a satellite simulator. This method determines the thermodynamic phases using the depolarization ratio and a cloud extinction proxy. For the evaluation, we introduced empirical parameterization of the depolarization ratio of ice and water clouds using temperatures of a reanalysis dataset and total attenuated backscatters of CALIPSO . We evaluated the
We intercompared the cloud properties of the DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains (DYAMOND) simulation output over the Atlantic Ocean. The domain averaged outgoing longwave radiation (OLR) is relatively similar across the models, but the net shortwave radiation at the top of the atmosphere (NSR) shows large differences among the models. The models capture the triple modes of cloud systems corresponding to shallow, congestus, and high clouds, although
As an alternative approach to previous multisensor satellite evaluations for cloud system resolving models (CSRMs), a technique for precipitation clouds over the ocean of CSRMs is presented using combined infrared and microwave channels. This method quantitatively analyzes precipitation clouds using cloud-top temperatures and ice scatterings from infrared 11 μm and high frequency microwave (89.0 GHz) brightness temperatures (TBs). The TB threshold at low frequencies (18.7 GHz) is used to identif
Abstract. The Cloud Profiling Radar (CPR) on the Earth Clouds, Aerosol, and Radiation Explorer (EarthCARE) satellite is the first satellite-borne Doppler radar (EC-CPR). In our previous study, we examined the effects of horizontal (along-track) integration and simple unfolding methods on the reduction of Doppler errors in the EC-CPR observations, and those effects were evaluated using two limited scenes in limited latitude and low pulse repetition frequency (PRF) settings. In this study, the amo
Abstract. Pre-launch simulated satellite data are useful to develop retrieval algorithms and to facilitate the rapid release of retrieval products after launch. Here we introduce the Japanese Aerospace Exploration Agency's (JAXA) EarthCARE synthetic data based on simulations using a 3.5 km horizontal-mesh global storm-resolving model. Global aerosol transport simulation results are added for aerosol retrieval developers. Synthetic data were produced corresponding to the four EarthCARE instrument
Abstract. A cloud identification and profiling algorithm is being developed for the multi-spectral imager (MSI), which is one of the four instruments that the Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE) spacecraft will feature. During recent work, we noticed that the MSI response function could shift substantially among some wavelengths (0.67 and 1.65 µm bands) owing to the spectral misalignment (SMILE), in which a shift in the center wavelength appears as a distortion in the spec
Abstract. The Cloud Profiling Radar (CPR) of the Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) has a new capability to observe the Doppler velocity related to the vertical air motion of the terminal velocity of hydrometeors. The new observation from space will be used to evaluate and improve the model. Before the launch of EarthCARE, we need to develop a methodology for using the CPR data for model evaluations. In this study, we evaluated simulated data by a stretched version of the gl
Abstract. This study introduces the primary products and features of active sensor-based Level 2 cloud products of the Japanese Aerospace Exploration Agency (JAXA). Combined with 94 GHz Doppler cloud radar and 355-nm high-spectral-resolution lidar, these products provide a detailed view of the transitions of cloud particle categories and their size distributions, as well as vertical velocity information. Simulated EarthCARE Level 1 data mimicking actual global observations were used to assess th
<p>It is important to evaluate and improve the cloud properties in global non-hydrostatic models like a Nonhydrostatic ICosahedral Atmospheric Model (NICAM, Satoh et al. 2014) using observation data. One of the methods is a radiance-based evaluation using satellite data and a satellite simulator (here Joint simulator, Hashino et al. 2013), which avoids making different settings of the microphysics between retrieval algorithms and NICAM.</p><p>The satelli
<strong>Overview</strong> These data are the Japanese Aerospace Exploration Agencies (JAXA) EarthCARE synthetic data based on simulations using a 3.5 km horizontal-mesh global storm-resolving model. Synthetic data were produced corresponding to the four EarthCARE instruments sensors, namely a 94 GHz cloud-profiling radar (CPR), a 355 nm atmospheric lidar (ATLID), a seven-channel multispectral imager (MSI), and a broadband radiometer (BBR). The data include a standard product with data for a sing
Abstract. The Cloud Profiling Radar (CPR) of the Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) has a new capability to observe the Doppler velocity related to the vertical air motion of the terminal velocity of hydrometeors. The new observation from space will be used to evaluate and improve the model. Before the launch of EarthCARE, we need to develop a methodology for using the CPR data for model evaluations. In this study, we evaluated simulated data by a stretched version of the gl
Understanding vertical motions in clouds is essential for improving weather and climate models but remains challenging due to limited observations. The newly launched EarthCARE satellite with a Doppler radar now provides global measurements of how fast particles fall through clouds, offering a way to estimate vertical air movements. In this study, we provide an initial assessment of EarthCARE’s Doppler radar observations by comparing them with high-resolution global simulations using NICAM and a
<strong class="journal-contentHeaderColor">Abstract.</strong> Pre-launch simulated data to be obtained from new sensors on a satellite is useful to develop retrieval algorithms and aid the rapid release of retrieval products after launch. Here we introduce Japanese Aerospace Exploration Agencies (JAXA) EarthCARE synthetic data based on simulations using a 3.5 km horizontal-mesh global storm-resolving model. Global aerosol transport simulation results are added for aerosol retrieval developers. S
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