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Background: High-fidelity meteorological data is a prerequisite for the realistic simulation of atmospheric dispersion of radioactive materials near nuclear power plants (NPPs). However, many meteorological models frequently overestimate near-surface wind speeds, failing to represent local meteorological conditions near NPPs. This study presents a new high-resolution (approximately 1 km) meteorological downscaling method for modeling short-range (< 100 km) atmospheric dispersion of accidental NPP plumes.Materials and Methods: Six considerations from literature reviews have been suggested for a new dynamic downscaling method. The dynamic downscaling method is developed based on the Weather Research and Forecasting (WRF) model version 3.6.1, applying high-resolution land-use and topography data. In addition, a new subgrid-scale topographic drag parameterization has been implemented for a realistic representation of the atmospheric surface-layer momentum transfer. Finally, a year-long simulation for the Kori and Wolsong NPPs, located in southeastern coastal areas, has been made for 2016 and evaluated against operational surface meteorological measurements and the NPPs’ on-site weather stations.Results and Discussion: The new dynamic downscaling method can represent multiscale atmospheric motions from the synoptic to the boundary-layer scales and produce three-dimensional local meteorological fields near the NPPs with a 1.2 km grid resolution. Comparing the year-long simulation against the measurements showed a salient improvement in simulating near-surface wind fields by reducing the root mean square error of approximately 1 m/s. Furthermore, the improved wind field simulation led to a better agreement in the Eulerian estimate of the local atmospheric dispersion. The new subgrid-scale topographic drag parameterization was essential for improved performance, suggesting the importance of the subgrid-scale momentum interactions in the atmospheric surface layer.Conclusion: A new dynamic downscaling method has been developed to produce high-resolution local meteorological fields around the Kori and Wolsong NPPs, which can be used in short-range atmospheric dispersion modeling near the NPPs.

Pharyngeal pouches, a series of outgrowths of the pharyngeal endoderm, are a key epithelial structure governing facial skeleton development in vertebrates. Pouch formation is achieved through collective cell migration and rearrangement of pouch-forming cells controlled by actin cytoskeleton dynamics. While essential transcription factors and signaling molecules have been identified in pouch formation, regulators of actin cytoskeleton dynamics have not been reported yet in any vertebrates. Cofilin1-like (Cfl1l) is a fish-specific member of the Actin-depolymerizing factor (ADF)/Cofilin family, a critical regulator of actin cytoskeleton dynamics in eukaryotic cells. Here, we report the expression and function of

In this study, the effects of bias correction methods on the daily precipitation in South Korea produced by five regional climate models (RCMs), and the impact of bias-corrected precipitation on projected climate change is investigated. We use four bias correction methods (Linear Scaling (LS) Power Transformation (PT), Quantile Mapping for the entire period (QME), and Quantile Mapping for each month (QMM)). We perform pre-processing corrections for the dry period in advance of QME and QMM for the wet period. All bias correction methods improve both long-term temporal and spatial averaged precipitation in the present-day period. However, the second peak of the annual precipitation cycle in the QME method is underestimated. LS shows poor correction skills for the intensity and frequency of extreme precipitation. The pre-processing for the dry period also helps to correct the intensity and frequency of daily precipitation. The corrected precipitation characteristics could vary depending upon the bias correction method. Thus, bias correction methods must be carefully chosen according to the statistical features such as the mean and extreme values that should be corrected. For future analysis, PT and QMM are only applied to improve daily precipitation. RCMs simulate the increase in precipitation mainly in the southern regions of Korea. RCMs also show that the second precipitation peak of the annual cycle is significantly strengthened. The intensity of extreme precipitation is increased significantly in the projection of the two scenarios. Bias correction can contribute to the improvement of precipitation variability retaining the characteristics of raw RCM data.

This study investigates the performance of simulated precipitation and estimates future changes in precipitation in CORDEX-East Asia Phase I. In the Historical experiment (1981–2005), a global climate model used as a lateral boundary condition does not realistically simulate the timing and intensity of the East Asian summer monsoon. Hence, it overestimates precipitation over East Asia. Generally, the results of the regional climate models also show similar bias characteristics to that of the large-scale forcing data. The individual biases of the regional climate model vary according to a model configuration, such as physical parameterization schemes. However, when bias correction is applied to data, the spatial variability and spatial correlation of the long-term mean precipitation become similar to the observations, and the annual cycle of precipitation is much improved. The two future experiments in the mid-twenty-first century period (2025–2049), show that mean and extreme precipitation amounts increase over the Korean Peninsula and northern China compared to the frequency of wet days. The increment of the low-level water vapor in all seasons can be attributed to the increased precipitation amounts; moreover, the East Asian summer monsoon is enhanced in mid-latitudes and lasts longer in summer owing to the strengthened western North Pacific Subtropical High. The increasing southerly wind from the East Asian summer monsoon over eastern China and the Korean Peninsula results in favorable conditions for the increase in precipitation.

Inka box actin regulator 1 (Inka1) is a novel protein identified in Xenopus and is found in vertebrates. While Inka1 is required for facial skeletal development in Xenopus and zebrafish, it is dispensable in mice despite its conserved expression in the cranial neural crest, indicating that Inka1 function in facial skeletal development is not conserved among vertebrates. Zebrafish bears two paralogs of inka1 (inka1a and inka1b) in the genome, with the biological roles of inka1b barely known. Here, we analyzed the expression and function of inka1b during facial skeletal development in zebrafish. inka1b was expressed sequentially in the head mesoderm adjacent to the pharyngeal pouches essential for facial skeletal development at the stage of arch segmentation. However, a loss-of-function mutation in inka1b displayed normal head development, including the pouches and facial cartilages. The normal head of inka1b mutant fish was unlikely a result of the genetic redundancy of inka1b with inka1a, given the distinct expression of inka1a and inka1b in the cranial neural crest and head mesoderm, respectively, during craniofacial development. Our findings suggest that the inka1b expression in the head mesoderm might not be essential for head development in zebrafish.

Future changes in tropical cyclone (TC) activity over the western North Pacific (WNP) are analyzed using four regional climate models (RCMs) within the Coordinated Regional Climate Downscaling Experiment (CORDEX) for East Asia. All RCMs are forced by the HadGEM2-AO under the historical and representative concentration pathway (RCP) 8.5 scenarios, and are performed at about 50-km resolution over the CORDEX-East Asia domain. In the historical simulations (1980–2005), multi-RCM ensembles yield realistic climatology for TC tracks and genesis frequency during the TC season (June–November), although they show somewhat systematic biases in simulating TC activity. The future (2024–49) projections indicate an insignificant increase in the total number of TC genesis (+5%), but a significant increase in track density over East Asia coastal regions (+17%). The enhanced TC activity over the East Asia coastal regions is mainly related to vertical wind shear weakened by reduced meridional temperature gradient and increased sea surface temperature (SST) at midlatitudes. The future accumulated cyclone energy (ACE) of total TCs increases significantly (+19%) because individual TCs have a longer lifetime (+6.6%) and stronger maximum wind speed (+4.1%) compared to those in the historical run. In particular, the ACE of TCs passing through 25°N increases by 45.9% in the future climate, indicating that the destructiveness of TCs can be significantly enhanced in the midlatitudes despite the total number of TCs not changing greatly.

Thehead gap gene buttonhead (btd) is required for the patterning of head segments in the early Drosophila embryo. Mutant phenotypes of btd display a gap-like phenotype in which antennal, intercalary, mandibular and the anterior portion of the maxillary segmentsare eliminated. In agreement with the phenotypes, btd is expressed in a stripe covering the head segments at the blastoderm stage. During the early phase of the germband extension, btd is expressed in stripes with single segmental periodicity, which is required for the formation of the peripheral nervous system. In contrast to the key role of btd in Drosophila embryonic development, it has been suggested that Tribolium ortholog of btd (Tc-btd) is dispensable for embryonic head development. In order for better understanding of the requirement of Tc-btd in the early Tribolium embryo, we re-analyzed the expression patterns and functions of Tc-btd during embryonic segmentation. Tc-btd is expressed in segmental stripes at the stages of blastoderm and germband elongation. Up to 28.3% of embryos in which Tc-btd is knocked down displays the loss of antennal, mandibular and the pregnathal regions in the head, with abdominal segments being disrupted in the trunk. Our findings suggest that Tc-btd is required for the head and trunk development in the early Tribolium embryo.

Epidermal growth factor-like domain multiple 6 (Egfl6) is a basement membrane protein and plays an important role in hair follicle morphogenesis, angiogenesis, notochord development in vertebrates. Although egfl6 expression in the developing head was observed in zebrafish, its role for craniofacial development and the determination of the pharyngeal region expressing egfl6, have not been reported yet. Here, we report the expression patterns and function of egfl6 in craniofacial development in zebrafish. egfl6 was expressed sequentially in the developing pharyngeal pouches that are key epithelial structures governing the development of the vertebrate head. However, loss-of-function mutations in egfl6 did not cause any craniofacial defects, including the pouches as well as the thymus and facial cartilages whose development is contingent upon appropriate pouch formation. egfl6 was unlikely redundant with egfl7 expressed in a distinct pharyngeal region from that of egfl6 in craniofacial development because reduction of egfl7 with a MO in egfl6 mutants did not affect craniofacial development. In addition, we found that egfl6 carried an endogenous start loss mutation in the wild-type T��bingen strain, implying egfl6 would be a non-functional gene. Taken all together, we suggest that egfl6 expression in the pharyngeal pouches is not required for craniofacial development in zebrafish.

The pharyngeal pouches are a series of epithelial outgrowths of the foregut endoderm. Pharyngeal pouches segment precursors of the vertebrate face into pharyngeal arches and pattern the facial skeleton. These pouches fail to develop normally in zebrafish foxi1 mutants, yet the role Foxi1 plays in pouch development remains to be determined. Here we show that ectodermal Foxi1 acts downstream of Fgf8a during the late stage of pouch development to promote rearrangement of pouch-forming cells into bilayers. During this phase, foxi1 and wnt4a are coexpressed in the facial ectoderm and their expression is expanded in fgf8a mutants. foxi1 expression is unaffected in wnt4a mutants; conversely, ectodermal wnt4a expression is abolished in foxi1 mutants. Consistent with this, foxi1 mutant pouch and facial skeletal defects resemble those of wnt4a mutants. These findings suggest that ectodermal Foxi1 mediates late-stage pouch morphogenesis through wnt4a expression. We therefore propose that Fox1 activation of Wnt4a in the ectoderm signals the epithelial stabilization of pouch-forming cells during late-stage of pouch morphogenesis.

Nanos proteins are essential for developing primordial germ cells (PGCs) in both invertebrates and vertebrates. In invertebrates, also contribute to the patterning of the anterior-posterior axis of the embryo and the neural development. In vertebrates, however, besides the role of Nanos proteins in PGC development, the biological functions of the proteins in normal development have not yet been identified. Here, we analyzed the expression and function of nanos1 during craniofacial development in zebrafish. nanos1 was expressed in the pharyngeal endoderm and endodermal pouches essential for the development of facial skeletons and endocrine glands in the vertebrate head. However, no craniofacial defects, such as abnormal pouches, hypoplasia of the thymus, malformed facial skeletons, have been found in nanos1 knockout animals. The normal craniofacial development of nanos1 knockout animals is unlikely a consequence of the genetic redundancy of Nanos1 with Nanos2 or Nanos3 or a result of the genetic compensation for the loss of Nanos1 by Nanos2 or Nanos3 because the expression of nanos2 and nanos3 was rarely seen in the pharyngeal endoderm and endodermal pouches in wild-type and nanos1 mutant animals during craniofacial development. Our findings suggest that nanos1 expression in the pharyngeal endoderm might be dispensable for craniofacial development in zebrafish.

A total of three binary tropical cyclone (TC) cases over the Western North Pacific are selected to investigate the effects of satellite radiance data assimilation on analyses and forecasts of binary TCs. Two parallel cycling experiments with a 6 h interval are performed for each binary TC case, and the difference between the two experiments is whether satellite radiance observations are assimilated. Satellite radiance observations are assimilated using the Weather Research and Forecasting Data Assimilation (WRFDA)'s three-dimensional variational (3D-Var) system, which includes the observation operator, quality control procedures, and bias correction algorithm for radiance observations. On average, radiance assimilation results in slight improvements of environmental fields and track forecasts of binary TC cases, but the detailed effects vary with the case. When there is no direct interaction between binary TCs, radiance assimilation leads to better depictions of environmental fields, and finally it results in improved track forecasts. However, positive effects of radiance assimilation on track forecasts can be reduced when there exists a direct interaction between binary TCs and intensities/structures of binary TCs are not represented well. An initialization method (e.g., dynamic initialization) combined with radiance assimilation and/or more advanced DA techniques (e.g., hybrid method) can be considered to overcome these limitations.

This study investigates long‐term trends in tropical cyclones (TCs) over the extratropical western North Pacific (WNP) over a period of 35 years (1982–2016). The area analyzed extended across 30–45°N and 120–150°E, including the regions of Korea and Japan that were seriously affected by TCs. The northward migration of TCs over the WNP to the mid‐latitudes showed a sharp increase in early fall. In addition, the duration of TCs over the WNP that migrated northwards showed an increase, specifically in early to mid‐September. Therefore, more recently, TC tracks have been observed to significantly extend into the mid‐latitudes. The recent northward extension of TC tracks over the WNP in early fall was observed to be associated with changes in environmental conditions that were favorable for TC activities, including an increase in sea surface temperature (SST), decrease in vertical wind shear, expansion of subtropical highs, strong easterly steering winds, and an increase in relative vorticity. In contrast, northward migrations of TCs to Korea and Japan showed a decline in late August, because of the presence of unfavorable environmental conditions for TC activities. These changes in environmental conditions, such as SST and vertical wind shear, can be partially associated with the Pacific decadal oscillation.

We determined the toxicity of mixtures of ethyl acetate (EA), isopropyl alcohol (IPA), methyl ethyl ketone (MEK), toluene (TOL) and xylene (XYL) with half-maximal effective concentration (EC50) values obtained using human hepatocytes cells. According to these data, quantitative property-activity relationships (QPAR) models were successfully proposed to predict the toxicity of mixtures by multiple linear regressions (MLR). The leave-one-out cross validation method was used to find the best subsets of descriptors in the learning methods. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP) and flash point (FP) were observed between the single substances and the mixtures. The EC50 of the mixture of EA and IPA was significantly lower than that of contained TOL and XYL. The mixture toxicity was related to the mixing ratio of MEK, TOL and XYL (MLR equation EC50 = 3.3081 − 2.5018 × TOL − 3.2595 × XYL − 12.6596 × MEK × XYL), as well as to BP, SG, VP and FP (MLR equation EC50 = 1.3424 + 6.2250 × FP − 7.1198 × SG × FP − 0.03013 × rVP × FP). These results suggest that QPAR-based models could accurately predict the toxicity of polar and nonpolar mixtures used in rotogravure printing industries.

In this study, the regional climate of the Korean Peninsula (KP) was dynamically downscaled using a high-resolution regional climate model (RCM) forced by multi- representative concentration pathways (RCP) scenarios of HadGEM2-AO, and changes in summer precipitation were investigated. Through the evaluation of the present climate, the RCM reasonably reproduced long-term climatology of summer precipitation over the KP, and captured the sub-seasonal evolution of Changma rain-band. In future projections, all RCP experiments using different RCP radiative forcings (i.e., RCP2.6, RCP4.5, RCP6.0, and RCP8.5 runs) simulated an increased summer precipitation over the KP. However, there were some differences in changing rates of summer precipitation among the RCP experiments. Future increases in summer precipitation were affected by future changes in moisture convergence and surface evaporation. Changing ranges in moisture convergences among RCP experiments were significantly larger than those in surface evaporation. This indicates that the uncertainty of changes in summer precipitation is related to the projection of the monsoon circulation, which determines the moisture convergence field through horizontal advection. Changes in the sub-seasonal evolution of Changma rain-band were inconsistent among RCP experiments. However, all experiments showed that Changma rain-band was enhanced during late June to early July, but it was weakened after mid-July due to the expansion of the western North Pacific subtropical high. These results indicate that precipitation intensity related to Changma rain-band will be increased, but its duration will be reduced in the future.

Intense tropical cyclones (TCs) accompanying torrential rain and powerful wind gusts often cause substantial socio-economic losses in the regions around their landfall. This study analyzes intense TCs in the North Atlantic (NA) and the western North Pacific (WNP) basins during the period 1982–2013. Different intensity criteria are used to define intense TCs for these two basins, category 1 and above for NA and category 3 and above for WNP, because the number of TCs in the NA basin is much smaller than that in the WNP basin. Using a fuzzy clustering method, intense TC tracks in the NA and the WNP basins are classified into two and three representative patterns, respectively. On the basis of the clustering results, a track-pattern-based model is then developed for forecasting the seasonal activities of intense TCs in the two basins. Cross-validation of the model skill for 1982–2013 as well as verification of a forecast for the 2014 TC season suggest that our intense TC model is applicable to operational uses.

The ability of five regional climate models (RCMs), within the Coordinated Regional Climate Downscaling Experiment (CORDEX) for East Asia, to simulate tropical cyclone (TC) activity over the western North Pacific is evaluated. All RCMs are performed at ~50 km resolution over the CORDEX-East Asia domain, and are driven by the ECMWF Interim Re-Analysis (ERA-Interim) for the period 1989–2008. ERA-Interim sea surface temperature is prescribed as the lower boundary. Performances of the individual RCMs and multi-RCM ensemble mean are investigated in detail for 20-year climatology, intensity, and interannual variability of TC activity compared to observational datasets. Although most of the individual RCMs show significant biases and underestimate TC intensity due to horizontal resolutions still too low to resolve the most intense observed TCs, they reasonably capture the observed climatological spatial distribution and interannual variability of TC activity. The multi-RCM ensemble mean based on the model performance generally outperforms most of the individual models with smaller biases and higher correlation on the spatial and temporal variation of TC activity. This ensemble mean reduces the uncertainty in the simulated TC activity by a single RCM. These analyses suggest that the multi-RCM ensemble within CORDEX-East Asia can be applied to provide more reliable and credible estimation of future TC activity over the western North Pacific due to climate change.

Impacts of coupled air–sea interaction and large-scale nudging were examined through regional climate simulation of the East Asian summer monsoon (EASM). A slab ocean model (SOM) was coupled with a regional climate model (RCM) to investigate the impact of two-way air–sea interaction, and the spectral nudging was applied to examine the effect of large-scale nudging. The control run without coupled air–sea interaction and large-scale nudging had significantly large systematic errors in simulated oceanic precipitation, monsoon circulations, and subtropical high. The errors resulted from an erroneous physical process caused by uncoupled air–sea interaction. The experiment with a SOM reduced the unreasonable physical process because simulated sea surface temperature (SST) decreases with enhanced ocean surface mixing from intensified low-level wind. Therefore, coupled air–sea interaction in the SOM run improved the simulations of seasonal mean precipitation, monsoon circulations, and subtropical high. In the experiment with a SOM and large-scale nudging, simulated precipitation and synoptic fields were further improved because the spectral nudging decreased the systematic error of large-scale circulations between model solution and large-scale forcing. Simulated results indicated that adjusting simulated SST to atmospheric conditions by coupling an ocean model with a RCM and improving boundary conditions by implementing large-scale nudging are necessary for advanced simulation of the EASM using RCMs.

In this study, global climate change scenario by HadGEM2-AO is dynamically downscaled using 5 Regional Climate Models (RCMs) for the Coordinated Regional Downscaling Experiment (CORDEX) - East Asia. All RCMs with 50-km horizontal resolution are integrated for continuous 71 years (1979-2049). In the evaluation of historical runs, all models tend to overestimate precipitation over the subtropical western North Pacific. For the surface air temperature, all models have cold biases over the East Asian continent compared to the observation. In the future projections, all models show similar changes in precipitation such as increasing precipitation over the tropical oceans and slightly decreasing precipitation over the East China Sea. In the mid-latitudes, convective precipitation tends to increase due to the enhanced convective instability, while non-convective precipitation tends to decrease slightly due to the changes in subtropical high and monsoon circulation. For surface air temperature, the warming tendency over the entire domain is captured by all models and it is larger in high latitude regions. The warming temperature is related to the increase in longwave radiation, which leads to prominent increase in minimum surface air temperature.

Recent changes of surface particulate matter (PM) concentration in the Seoul Metropolitan Area (SMA), South Korea, are puzzling. The long-term trend of surface PM concentration in the SMA declined in the 2000s, but since 2012 its concentrations have tended to incline, which is coincident with frequent severe hazes in South Korea. This increase puts the Korean government’s emission reduction efforts in jeopardy. This study reports that interannual variation of surface PM concentration in South Korea is closely linked with the interannual variations of wind speed. A 12-year (2004–2015) regional air quality simulation was conducted over East Asia (27-km) and over South Korea (9-km) to assess the impact of meteorology under constant anthropogenic emissions. Simulated PM concentrations show a strong negative correlation (i.e. R = −0.86) with regional wind speed, implying that reduced regional ventilation is likely associated with more stagnant conditions that cause severe pollutant episodes in South Korea. We conclude that the current PM concentration trend in South Korea is a combination of long-term decline by emission control efforts and short-term fluctuation of regional wind speed interannual variability. When the meteorology-driven variations are removed, PM concentrations in South Korea have declined continuously even after 2012.

Tropical cyclones (TCs) over the western North Pacific (WNP) are simulated for the 29 TC seasons of July–October from 1982 to 2010 using the regional Weather Research and Forecasting (WRF) model nested within global WRF model simulations. Averaged over the entire 29-year period, the nested global–regional WRF has reasonably simulated the climatology of key TC features such as the location/frequency of genesis and tracks. The dynamical and thermal structures of the simulated TCs are weaker than observations owing to the coarse spatial resolution of the regional WRF (50 km × 50 km). TC frequencies are somewhat underestimated over the East China Sea but are substantially overestimated over the South China Sea and the Philippine Sea with neighboring oceans between 10°N and 15°N. Categorization of the simulated TCs into six clusters based on the observed TC clusters and the associated large-scale circulation show that the nested simulation depicts the observed TC characteristics well except for two clusters associated with TCs traveling from the Philippine Sea to the East China Sea. Errors in the simulated TC genesis and tracks are mostly related to these two clusters. In the simulation, the monsoon confluent zone over the Philippine Sea is too strong, and the mid-latitude jet stream expands farther south than that in the observations. Overall results from this study suggest that the nested global–regional WRF can be useful for studying the TC climatology over the WNP.

The automated prediction system for seas onal tropical cyclone (TC) activity isestablished at the National Typhoon Center of the Korea Meteorological Administration(KMA) to provide effective operation and control of the system for user who lacks knowledgeof the system. For automation of the system, two procedures which include subjective deci-sions by user are performed in advance, and th eir output data are provided as input data. Toprovide the capability to understand the opera tional processes for operational user, the inputand output data are summarized with each process, and the directory structure is reconstructedfollowing KMA’s standard. We introduce a user interface using namelist input parameters toeffectively control operational conditions which is fixed or should be manually set in the previ-ous version of the prediction system. To operationally use early prediction which become avail-able through the automation, its performances are evaluated according to initial conditiondates. As a result, high correlations between the observed and predicted TC counts are kept forall track clusters even though advancing the initial condition date from May to January.

In this study, regional climate changes for seventy years (1980–2049) over East Asia and the Korean Peninsula are investigated using the Special Reports on Emission Scenarios (SRES) B1 scenario via a high-resolution regional climate model, and the impact of global warming on extreme climate events over the study area is investigated. According to future climate predictions for East Asia, the annual mean surface air temperature increases by 1.8°C and precipitation decreases by 0.2 mm day−1 (2030–2049). The maximum wind intensity of tropical cyclones increases in the high wind categories, and the intra-seasonal variation of tropical cyclone occurrence changes in the western North Pacific. The predicted increase in surface air temperature results from increased longwave radiations at the surface. The predicted decrease in precipitation is caused primarily by northward shift of the monsoon rain-band due to the intensified subtropical high. In the nested higher-resolution (20 km) simulation over the Korean Peninsula, annual mean surface air temperature increases by 1.5°C and annual mean precipitation decreases by 0.2 mm day−1. Future surface air temperature over the Korean Peninsula increases in all seasons due to surface temperature warming, which leads to changes in the length of the four seasons. Future total precipitation over the Korean Peninsula is decreased, but the intensity and occurrence of heavy precipitation events increases. The regional climate changes information from this study can be used as a fruitful reference in climate change studies over East Asia and the Korean peninsula.

Observational records reveal that the number of tropical cyclones (TCs) approaching East Asia in July–October is positively correlated with sea surface temperatures (SSTs) in the equatorial and northern off-equatorial central Pacific (CP) oceans, indicating the significant impact of CP El Niño (CP-EN). Through experiments using a Weather Research and Forecast (WRF) model–based regional climate model, this study demonstrates that it is northern off-equatorial CP warming, rather than equatorial CP warming, that effectively induces local anomalous steering flows pertinent to the observed increase in TC activity over East Asia during CP-EN. Sensitivity experiments, in which the prescribed CP-EN-related SST anomaly is confined near the equator, do not capture the observed TC increase over East Asia, whereas those including the off-equatorial region successfully reproduce observed atmospheric and TC variabilities. The off-equatorial CP SST anomaly acts to expand the anomalous cyclonic response in the Philippine Sea farther northward. This produces a tunnel effect in the East China Sea, by which more TCs move to East Asian coastal regions (e.g., east China, Taiwan, Korea, and Japan).

We demonstrate that daily pollutant transport patterns in East Asia are visible from satellite images when inspected with corresponding synoptic weather analyses. Transport pathways of air pollutants in East Asia are investigated using satellite observations, surface weather charts, and chemical-transport model simulations. It is found that during cool season (fall to spring), pollutant transports in East Asia are largely determined by synoptic weather patterns associated with high pressure system over southern China, which is extended from the Siberia High, and low pressure system over Manchuria, which is initiated by Altai-Sayan cyclogenesis. Based on the relative location and strength of these weather systems, three types of synoptic weather patterns that may contribute to pollutants transport in East Asia, especially in China and Korea, are identified: i.e., (1) a strengthening of the Siberian High and its southeastward propagation; (2) a high-pressure system over southern China followed by a frontal passage associated with a northern low-pressure system; and (3) a stagnant high-pressure system over southern China. For all three patterns, the high-pressure system in southern China is essential for the development of regional air pollution, while frontal activities associated with low-pressure system provide a forcing mechanism to transport those pollutants eastward or southeastward. Observed and simulated surface PM distributions show good agreement in both aerosol optical depth and NO2 column density further implying that anthropogenic emissions also contribute to regional events of high surface PM concentrations. It is argued that the quasi-periodic migration of synoptic weather systems in East Asia works as an efficient pump of pollutants; i.e., regional air pollutions developed under high-pressure systems are transported downstream by low-pressure systems.

There is no doubt that the therapeutic efficacy of mesenchymal stem cells (MSCs) needs improvement. SDF-1 (chemokine for MSC homing) and its receptor CXCR4 play a critical role in the migration of MSCs in ischemia. We investigated the effects of the therapeutic application of MSCs transfected to overexpress CXCR4 using an adenoviral construct in the rat stroke model. Both flow cytometry and Western blot analysis indicated that the level of CXCR4 expression was low in naive hMSCs but was consistently high in CXCR4-hMSCs. In vivo migration test using the transwell system showed that the degree of migration was increased in CXCR4-hMSCs compared with the naive hMSCs and was completely blocked by treatment with AMD3100, an antagonist of the CXCR4 receptor. Compared with rats that received naive MSCs, behavioral recovery was more pronounced in rats that received CXCR4-hMSCs ( p = 0.023). An immunohistochemistry study using human nuclear antibody (NuMA) showed that the migration of hMSCs in the ischemic boundary zone was increased after 3 days of injection of CXCR4-hMSCs compared with after injection of naive hMSCs. In addition, polymerase chain reaction was performed to assess the biodistribution of human-specific DNA outside the brain after intravenous injection of hMSCs. The expression of human-specific DNA was increased in the lungs of rats receiving naive MSCs, whereas the human-specific DNA expression was increased in the brain of rats receiving CXCR4-hMSCs. Our results indicate that MSCs transfected with the CXCR4 gene expression cassette may be useful in the treatment of cerebral infarction and may represent a new strategy to enhance the efficacy of MSC therapy.

In this paper, the prediction skills of five ensemble methods for temperature and precipitation are discussed by considering 20 yr of simulation results (from 1989 to 2008) for four regional climate models (RCMs) driven by NCEP–Department of Energy and ECMWF Interim Re-Analysis (ERA-Interim) boundary conditions. The simulation domain is the Coordinated Regional Downscaling Experiment (CORDEX) for East Asia, and the number of grid points is 197 × 233 with a 50-km horizontal resolution. Three new performance-based ensemble averaging (PEA) methods are developed in this study using 1) bias, root-mean-square errors (RMSEs) and absolute correlation (PEA_BRC), RMSE and absolute correlation (PEA_RAC), and RMSE and original correlation (PEA_ROC). The other two ensemble methods are equal-weighted averaging (EWA) and multivariate linear regression (Mul_Reg). To derive the weighting coefficients and cross validate the prediction skills of the five ensemble methods, the authors considered 15-yr and 5-yr data, respectively, from the 20-yr simulation data. Among the five ensemble methods, the Mul_Reg (EWA) method shows the best (worst) skill during the training period. The PEA_RAC and PEA_ROC methods show skills that are similar to those of Mul_Reg during the training period. However, the skills and stabilities of Mul_Reg were drastically reduced when this method was applied to the prediction period. But, the skills and stabilities of PEA_RAC were only slightly reduced in this case. As a result, PEA_RAC shows the best skill, irrespective of the seasons and variables, during the prediction period. This result confirms that the new ensemble method developed in this study, PEA_RAC, can be used for the prediction of regional climate.

In this study, the anomalous characteristics of observed large-scale synoptic fields in the extreme East Asian summer monsoon (EASM) years are analyzed, and the impact of the local sea surface temperature (SST) anomaly over the western North Pacific (WNP) on the extreme EASM is investigated through sensitivity experiments of 28 years EASM simulations to the local SST over the WNP. The observation analysis reveals that the extreme EASM is influenced more by anomalous large-scale atmospheric features such as monsoon circulations and the western North Pacific subtropical high than the local SST anomaly over the WNP. However, the results of the sensitivity experiments show that the local SST anomaly has an implicit impact on the extreme EASM. The patterns of differences in precipitation between the experiment forced by observed SST in each year and the experiment forced by climatological SST over the WNP are opposite to anomaly patterns of observed precipitation in the extreme EASM years. This is because the SST anomaly over the WNP plays a role in reducing precipitation anomaly by changing surface latent heat flux and monsoon circulations. In particular, the local SST anomaly over the WNP decreases anomalies of large-scale circulations, i.e., the local Hadley and the Walker circulations. Thus, the local SST anomaly over the WNP plays a role in decreasing the interannual variability of the EASM.

To evaluate the optimal timing of mesenchymal stem cell (MSC) transplantation following stroke, rats were transplanted with MSCs at 1 (D1), 4 (D4), and 7 days (D7) after middle cerebral artery occlusion (MCAo). Rats in the D1 group showed a better functional recovery than those in the D4 or D7 groups after MCAo. MSCs preferentially migrated to the cortex in the D1 group, while the MSCs in the D4 or D7 groups preferentially migrated to the striatum. Interestingly, the level of monocyte chemotactic protein-1 (MCP-1) in the cortex was highest at 1 day after MCAo, while the level of stromal cell-derived factor-1 (SDF-1) in the striatum was lowest at 1 day after MCAo and then increased over time. The pattern of MCP-1 and SDF-1 level changes according to the time after MCAo was consistent with in vivo and in vitro migration patterns of MSCs. The results suggest that an earlier MSC transplantation is associated with a better functional recovery after stroke, which could be explained by the preferential migration of MSCs to the cortex in the early transplantation group. The time-dependent differential expression of MCP-1 and SDF-1 between ischemic regions seemed to mediate the differential migration of MSCs. Highest level of MCP-1 at one day of stroke may induce preferential migration of MSCs to the cortex, then better functional improvement.

In the Arctic, climate warming enhances vegetation activity by extending the length of the growing season and intensifying maximum rates of productivity. In turn, increased vegetation productivity reduces albedo, which causes a positive feedback on temperature. Over the Tibetan Plateau (TP), regional vegetation greening has also been observed in response to recent warming. Here, we show that in contrast to arctic regions, increased growing season vegetation activity over the TP may have attenuated surface warming. This negative feedback on growing season vegetation temperature is attributed to enhanced evapotranspiration (ET). The extra energy available at the surface, which results from lower albedo, is efficiently dissipated by evaporative cooling. The net effect is a decrease in daily maximum temperature and the diurnal temperature range, which is supported by statistical analyses of in situ observations and by decomposition of the surface energy budget. A daytime cooling effect from increased vegetation activity is also modeled from a set of regional weather research and forecasting (WRF) mesoscale model simulations, but with a magnitude smaller than observed, likely because the WRF model simulates a weaker ET enhancement. Our results suggest that actions to restore native grasslands in degraded areas, roughly one-third of the plateau, will both facilitate a sustainable ecological development in this region and have local climate cobenefits. More accurate simulations of the biophysical coupling between the land surface and the atmosphere are needed to help understand regional climate change over the TP, and possible larger scale feedbacks between climate in the TP and the Asian monsoon system.

[1] This study examines simulated typhoon sensitivities to spectral nudging (SN) to investigate the effects on values added by regional climate models, which are not properly resolved by low-resolution global models. SN is suitably modified to mitigate its negative effects while maintaining the positive effects, and the effects of the modified SN are investigated through seasonal simulations. In the sensitivity experiments to nudging intervals of SN, the tracks of simulated typhoons are improved as the SN effect increases; however, the intensities of the simulated typhoons decrease due to the suppression of the typhoon developing process by SN. To avoid such suppression, SN is applied at intermittent intervals only when the deviation between the large-scale driving forcing and the model solution is large. In seasonal simulations, intermittent SN is applied for only 7% of the total time steps; however, this results in not only maintaining the large-scale features of monsoon circulation and precipitation corresponding to observations but also improving the intensification of mesoscale features by reducing the suppression.