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국제학술지

공지 (2025. 10. 28.)

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Does El Niño-Southern Oscillation affect the precipitation in Korea on seasonal time scales?

A number of studies in the past two decades have attempted to find the relationship between the precipitation in Korea and the El Niño-Southern Oscillation (ENSO) on various time scales. Comprehensive analyses of station precipitation data in Korea for the 61-year period, 1954-2014, in this study show that the effects of ENSO on the seasonal precipitation in Korea are practically negligible. The correlation between summer precipitation and ENSO is insignificant regardless of the intensity, type (e.g., eastern-Pacific or central-Pacific), and stage (e.g., developing, mature, or decaying) of ENSO. Somewhat meaningful correlation between ENSO and precipitation in Korea occurs only in the ENSO-developing fall. Because summer rainfall accounts for over half of the annual total and fall is a dry season in Korea, the overall effects of ENSO on precipitation in Korea are practically nonexistent.
- 작성자Ho et al.
- 작성일2024.08.28
- 조회수57
- 2016
A track pattern–based seasonal prediction of tropical cyclone activity over the North Atlantic

A seasonal prediction model of tropical cyclone (TC) activities for the period August-October over the North Atlantic (NA) has been developed on the basis of TC track patterns. Using the fuzzy c-means method, a total of 432 TCs in the period 1965-2012 are categorized into the following four groups: 1) TCs off the East Coast of the United States, 2) TCs over the Gulf of Mexico, 3) TCs that recurve into the open oceans of the central NA, and 4) TCs that move westward in the southern NA. The model is applied to predict the four TC groups separately in conjunction with global climate forecasts from the National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 (CFSv2). By adding the distributions of the four TC tracks with pre-calculated weighting factors, this seasonal TC forecast model provides the spatial distribution of TC activities over the entire NA basin. Multiple forecasts initialized in six consecutive months from February to July are generated at monthly intervals to examine the applicability of this model in operational TC forecasting. Cross-validations of individual forecasts show that the model can reasonably predict the observed TC frequencies over NA at the 99% confidence level. The model shows a stable spatial prediction skill, proving its advantage for forecasting regional TC activities several months in advance. In particular, the model can generate reliable information on regional TC counts in the near-coastal regions as well as in entire NA basin.
- 작성자Choi et al.
- 작성일2024.08.28
- 조회수49
- 2016
Airborne measurements of high pollutant concentration events in the free troposphere over the West Coast

Aircrafts enable the direct measurement of chemical components in the free troposphere (FT). This study employed airborne measurements to examine the occurrences of high concentrations of SO2 and NOx in the FT over the coastal region west of the Seoul metropolitan area, South Korea. The data from a long-term (1997-2011) airborne measurement campaign were used to determine the meteorological conditions favorable for carrying these pollutants into the Seoul area. The back trajectory analyses of 21 instances of high FT pollutant concentration events showed ascending patterns from the major pollutant sources, mainly the industrial complexes in eastern China, in 9 instances and passing patterns in 12 instances. In the ascending instances, developing low-pressure systems over the source regions provide favorable conditions to uplift air pollutants from the surface into the FT. In the passing instances, an anomalous low-pressure system near the surface prevented airflows from descending into the boundary layer and upper-level anticyclonic systems helped to keep the ascending airflows in the FT. This study proposes the basic mechanisms for predicting air quality in the Seoul area, considering that air pollutants in the FT often entrain into the boundary layer to increase local concentrations.
- 작성자Lee et al.
- 작성일2024.08.28
- 조회수55
- 2016
Spatial and temporal changes in leaf coloring date of Acer palmatum and Ginkgo biloba in response to temperature...

Abstract: Understanding shifts in autumn phenology associated with climate changes is critical for preserving forest ecosystems. This study examines the changes in the leaf coloring date (LCD) of two temperate deciduous tree species, Acer palmatum (Acer) and Ginkgo biloba (Ginkgo), in response to surface air temperature (Ts) changes at 54 stations of South Korea for the period 1989–2007. The variations of Acer and Ginkgo in South Korea are very similar: they show the same mean LCD of 295th day of the year and delays of about 0.45 days year-1 during the observation period. The delaying trend is closely correlated (correlation coefficient > 0.77) with increases in Ts in mid-autumn by 2.8 days °C-1. It is noted that the LCD delaying and temperature sensitivity (days °C-1) for both tree species show negligible dependences on latitudes and elevations. Given the significant LCD-Ts relation, we project LCD changes for 2016–35 and 2046–65 using a process-based model forced by temperature from climate model simulation. The projections indicate that the mean LCD would be further delayed by 3.2 (3.7) days in 2016–35 (2046–65) due to mid-autumn Ts increases. This study suggests that the mid-autumn warming is largely responsible for the observed LCD changes in South Korea and will intensify the delaying trends in the future. Full title: Spatial and temporal changes in leaf coloring date of Acer palmatum and Ginkgo biloba in response to temperature increases in South Korea
- 작성자Park et al.
- 작성일2024.08.22
- 조회수73
- 2017
Tropical Cyclone Mekkhala's (2008) Formation over the South China Sea: Mesoscale, Synoptic-scale and Large-scale...

Tropical cyclone formation close to the coastline of the Asian continent presents a significant threat to heavily populated coastal countries. A case study of Tropical Storm Mekkhala (2008) that developed off the coast of Vietnam is presented using the high-resolution analyses of the European Centre for Medium-Range Weather Forecasts/Year of Tropical Convection and multiple satellite observations. The authors have analyzed contributions to the formation from large-scale intraseasonal variability, synoptic perturbations, and mesoscale convective systems (MCSs). Within a large-scale westerly wind burst (WWB) associated with the Madden–Julian oscillation (MJO), synoptic perturbations generated by two preceding tropical cyclones initiated the pre-Mekkhala low-level vortex over the Philippine Sea. Typhoon Hagupit produced a synoptic-scale wave train that contributed to the development of Jangmi, but likely suppressed the Mekkhala formation. The low-level vortex of the pre-Mekkhala disturbance was then initiated in a confluent zone between northeasterlies in advance of Typhoon Jangmi and the WWB. A key contribution to the development of Mekkhala was from diurnally varying MCSs that were invigorated in the WWB. The oceanic MCSs, which typically develop off the west coast of the Philippines in the morning and dissipate in the afternoon, were prolonged beyond the regular diurnal cycle. A combination with the MCSs developing downstream of the Philippines led to the critical structure change of the oceanic convective cluster, which implies the critical role of mesoscale processes. Therefore, the diurnally varying mesoscale convective processes over both the ocean and land are shown to have an essential role in the formation of Mekkhala in conjunction with large-scale MJO and the synoptic-scale TC influences.
- 작성자Park et al.
- 작성일2024.08.28
- 조회수74
- 2015
The effects of ENSO under negative AO phase on spring dust activity over northern China: An observational investigation

The effects of El Niño/Southern Oscillation (ENSO) under negative Arctic Oscillation (AO) phase on the Asian dust activity are investigated for springs of the period 1961–2002. The spring dust index (DI) describing the monthly frequencies of three types of dust events (e.g. dust storm, blowing dust, and floating dust) exhibits a significant increase in the years of negative AO phase (hereafter AO−) and El Niño, compared with that in the years of AO− and La Niña. Averaged over all observation stations, the spring DI (49.7) during the El Niño/AO− years is higher by 11.4% or 29.8% than that (38.3) during the La Niña/AO− years. We suggest possible physical mechanism that the anomalous large-scale environments associated with AO− and El Niño are more effective to provide favourable conditions to enhance Asian dust activity. During the El Niño/AO− years, meridional gradients of pressure and temperature over the dust source regions are significantly enhanced by decreasing the geopotential height and warming air temperature that originated from the north and south of source regions, respectively, under the influence of AO− and El Niño. These also intensify the zonal wind shear and atmospheric baroclinicity, thereby producing enhanced cyclogenesis and dust occurrences over the major source regions. At the same time, dust transport paths with the stronger westerly winds are developed by the combined constraints of anomalous cyclone over the Siberia and the Mongolia and anomalous anticyclone over the western North Pacific, and thus strengthen dust transport to the downwind regions.
- 작성자Lee et al.
- 작성일2024.08.28
- 조회수88
- 2015
Retrieval of outgoing longwave radiation from COMS narrowband infrared imagery

Hourly outgoing longwave radiation (OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite (COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm (OLR12.0 using the 12.0 μm channel) and three multiple-channel algorithms (OLR10.8+12.0 using the 10.8 and 12.0 μm channels; OLR6.7+10.8 using the 6.7 and 10.8 μm channels; and OLRAll using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth’s Radiant Energy System (CERES) over the full COMS field of view [roughly (50°S–50°N, 70°–170°E)] during April 2011. Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m−2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8 and OLRAll have much smaller errors (∼6 W m−2) than OLR12.0 and OLR10.8+12.0 (∼8 W m−2). Moreover, the small errors of OLR6.7+10.8 and OLRAll are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the 6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed.
- 작성자Park et al.
- 작성일2024.08.28
- 조회수68
- 2015
Regional variations in potential plant habitat changes in response to multiple global warming scenarios

This study examines the impacts of global warming on the timing of plant habitat changes in the twenty-first century using climate scenarios from multiple global climate models (GCMs). The plant habitat changes are predicted by driving the bioclimate rule in a dynamic global vegetation model using the climate projections from 16 coupled GCMs. The timing of plant habitat changes is estimated by the first occurrence of specified fractional changes (10%, 20%, and 30%). All future projections are categorized into three groups by the magnitude of the projected global-mean land surface temperature changes: low (3.5 K) warming. During the course of the twenty-first century, dominant plant habitat changes are projected in ecologically transitional (i.e., from tropical to temperate and temperate to boreal) regions. The timing of plant habitat changes varies substantially according to regions. In the low-warming group, habitat changes of 10% in southern Africa occur in 2028, earlier than in the Americas by more than 70 yr. Differences in the timing between regions increase with the increase in warming and fractional threshold. In the subtropics, fast plant habitat changes are projected for the Asia and Africa regions, where countries of relatively small gross domestic product (GDP) per capita are concentrated. Ecosystems in these regions will be more vulnerable to global warming, because countries of low economic power lack the capability to deal with the warming-induced habitat changes. Thus, it is important to establish international collaboration via which developed countries provide assistance to mitigate the impacts of global warming.
- 작성자Park et al.
- 작성일2024.08.28
- 조회수70
- 2015
Quiescence of Asian dust events in South Korea and Japan during 2012 spring: Dust outbreaks and transports

This study examined the quiescence of Asian dust events in South Korea and Japan during the spring of 2012, presenting a synoptic characterization and suggesting possible causes. Synoptic observation reports from the two countries confirmed that spring 2012 had the lowest number of dust events in 2000–2012. The monthly dust frequency (DF) in March 2012 over the dust source regions, i.e., deserts in northern China and Mongolia, indicated a significant decrease compared to the 12 year (2000–2011) March climatology. The DF in April 2012 was comparable to the 12 year climatology values, but in May 2012 it was slightly lower. The daily Ozone Monitoring Instrument Aerosol Index and the Navy Aerosol Analysis and Prediction System simulations revealed stagnant dust movement in March and May 2012. Anomalous anticyclones north of the source regions decreased the dust outbreaks and enhanced the southeasterly winds, resulting in few dust events over the downwind countries (i.e., South Korea and Japan). By contrast, in April 2012, a strong anomalous cyclone east of Lake Baikal slightly increased the dust outbreaks over northeastern China. However, the major dust outbreaks were not transported downwind because of exceptional dust pathways, i.e., the southeastward pathway of dust transport was unusually blocked by the expansion of an anomalous anticyclonic circulation over the Sea of Okhotsk, with dust being transported northeast.
- 작성자Lee et al.
- 작성일2024.08.28
- 조회수57
- 2015
Projection of summertime ozone concentration over East Asia under multiple IPCC SRES emission scenarios

We have developed the Integrated Climate and Air Quality Modeling System (ICAMS) through the one-way nesting of global–regional models to examine the changes in the surface ozone concentrations over East Asia under future climate scenarios. Model simulations have been conducted for the present period of 1996–2005 to evaluate the performance of ICAMS. The simulated surface ozone concentrations reproduced the observed monthly mean concentrations at sites in East Asia with high R2 values (0.4–0.9), indicating a successful simulation to capture both spatial and temporal variability. We then performed several model simulations with the six IPCC SRES scenarios (A2, A1B, A1FI, A1T, B1, and B2) for the next three periods, 2016–2025 (the 2020s), 2046–2055 (the 2050s), and 2091–2100 (the 2090s). The model results show that the projected changes of the annual daily mean maximum eight-hour (DM8H) surface ozone concentrations in summertime for East Asia are in the range of 2–8 ppb, −3 to 8 ppb, and −7 to 9 ppb for the 2020s, the 2050s, and the 2090s, respectively, and are primarily determined based on the emission changes of NOx and NMVOC. The maximum increases in the annual DM8H surface ozone and high-ozone events occur in the 2020s for all scenarios except for A2, implying that the air quality over East Asia is likely to get worse in the near future period (the 2020s) than in the far future periods (the 2050s and the 2090s). The changes in the future environment based on IPCC SRES scenarios would also influence the change in the occurrences of high-concentrations events more greatly than that of the annual DM8H surface ozone concentrations. Sensitivity simulations show that the emissions increase is the key factor in determining future regional surface ozone concentrations in the case of a developing country, China, whereas a developed country, Japan would be influenced more greatly by effects of the regional climate change than the increase in emissions.
- 작성자Lee et al.
- 작성일2024.08.28
- 조회수60
- 2015
Nonlinear response of vegetation green-up to local temperature variations in temperate and boreal forests in the...

The annual cycle of vegetation growth may be altered in response to climate changes affecting ecosystem dynamics. However, our understanding of vegetation seasonality is mostly limited to the mechanisms and attributes of phenological events, such as spring emergence and fall senescence. Here we have investigated the seasonal evolution of vegetation growth from winter dormancy to summer maturity of four forest types in the Northern Hemisphere (NH) temperate and boreal forests for 1982–2011. The present study assesses large-scale variations in the vegetation green-up rate (VGrate) and its connection to temperature variability using remotely sensed normalized difference vegetation index (NDVI) and surface air temperature. The average of the VGrate of the analysis period increases with latitude, which indicates that the canopy develops more rapidly from dormancy to maturity for vegetation in higher-latitude or colder climate zones. VGrate and precedent temperature also show a positive correlation (r) over temperate and boreal forests (67% of the forest area in the NH), indicating that increased temperatures lead to faster canopy development within the same climate zone or latitude band. Responsiveness of VGrate to temperature variability shows that despite the same magnitude of local temperature variability during extremely cold and warm years, the magnitude of VGrate acceleration in warm years (0.07 (15-day)− 1) is larger than the VGrate deceleration in cold years (− 0.03 (15-day)− 1), suggesting that the response of VGrate to temperature variability is nonlinear. Among the four forest types examined in this study, the nonlinear responses are most clearly observed in deciduous broadleaf forests indicating that forest composition may regulate the large-scale response of canopy development to temperature variability. Overall, our results suggest that anomalous seasonal warming will significantly affect canopy developments over wide deciduous forest areas.
- 작성자Park et al.
- 작성일2024.08.28
- 조회수61
- 2015
Long-range transport of air pollutants originating in China: A possible major cause of multi-day high-PM10 episodes...

Massive air pollutants originating in China and their trans-boundary transports are an international concern in East Asia. Despite its importance, details in the trans-boundary transport of air pollutants over East Asia and its impact on regional air quality remain to be clarified. This study presents an evidence which strong support that aerosols emitting in China play a major role in the occurrence of multi-day (≥4 days) severe air pollution episodes in cold seasons (October through March) for 2001–2013 in Seoul, Korea, where the concentration of PM10 (particulates with diameters ≤ 10 μm) exceeds 100 μg m−3. Observations show that these multi-day severe air pollution episodes occur when a strong high-pressure system resides over the eastern China–Korea region. In such weather conditions, air pollutants emitted in eastern China/southwestern Manchuria are trapped within the atmospheric boundary layer, and gradually spread into neighboring countries by weak lower tropospheric westerlies. Understanding of trans-boundary transports of air pollutants will advance the predictability of local air quality, and will encourage the development of international measures to improve air quality.
- 작성자Oh et al.
- 작성일2024.08.28
- 조회수116
- 2015
Future ozone and oxidants change under the RCP scenarios

We investigate ozone air quality changes in 2050 caused by global changes in climate and anthropogenic emissions of ozone precursors by using a global chemical transport model driven by meteorological fields from a general circulation model. We use projected emissions based on the Representative Concentration Pathway (RCP) scenarios and conduct model simulations to quantify the effects of climate and emission changes on future air quality, focusing on ozone in surface air. Our model results show that annual mean concentrations of surface ozone will be lower in 2050 relative to 2000 by −3.3, −3.7, and −4.2 ppbv under RCP6.0, RCP4.5, and RCP2.6, respectively. In contrast, the RCP8.5 projection results in a slight increase of 2.1 ppbv caused by a methane increase. The ozone reductions are driven primarily by decreases in NOx emission, which dominate the climate penalty on ozone driven by temperature increases. We also estimate the effect of 21st century climate change on ozone air quality, assuming no changes in anthropogenic emissions of ozone precursors in the future. We further use a statistical method to analyze the results in order to quantify the effect of each meteorological variable change on ozone concentration in summer. Temperature increase is found to result in ozone increases of up to 2.2 ppbv over land. Ozone over the oceans, however, is largely reduced with specific humidity increase, particularly in the Northern Hemisphere, where the ozone concentration decreases by 0.8 ppbv. We find that future increases in natural NOx emissions from lightning and soil make an important contribution to the formation of nitric acid and might seriously offset future decreases in nitrogen deposition caused by anthropogenic NOx emission reduction.
- 작성자Kim et al.
- 작성일2024.08.28
- 조회수62
- 2015
Evidence of reduced vulnerability against tropical cyclones in the Republic of Korea

On average, three tropical cyclones (TCs) affect the Republic of Korea each year, causing extensive damage. To alleviate the TC-induced disasters, the Korean government has invested nearly 4% of its annual budget in recent decades in prevention efforts; however, the effectiveness of this costly program has not been evaluated. This study determined whether any evidence shows a reduced vulnerability to TCs in Korea over 1979–2010 by utilizing multi-linear regression. Homelessness, casualties, and property losses were individually examined. These explained variables were normalized into the socio-economic circumstances of 2005 before the regression to eliminate the effect of changing exposure by dealing with population and wealth at provincial levels. Three potential explanatory variables based on nationwide weather-station data were considered, including the maximum wind, maximum rainfall, and number of affected stations over each TC's damaging period. In addition, the annual per capita income, showing a quasi-linear increasing tendency, was used as an additional explanatory variable to examine how vulnerability is altered. The results revealed that each empirical model of homelessness, casualties, and property losses can account for 47%, 57%, and 57% of each variance, respectively, which is highest when considering all four explanatory variables. Consistently negative coefficients of the per capita income terms for all damage types suggest that the vulnerability to TCs has been significantly reduced. This finding appears to be partly the result of the national prevention effort, although it also can be attributed to other unintended adaptation factors, such as building codes, industrial structures, and land use.
- 작성자Park et al.
- 작성일2024.08.28
- 조회수66
- 2015
Earth and environmental remote sensing community in South Korea: A review

This paper is a review of the satellite remote sensing community in South Korea, in the field of Earth and environmental sciences. The community has been invigorated by the Communication, Ocean, and Meteorological Satellite (COMS), the first Korean geostationary satellite project. Since its successful launch on July 26, 2010, about 300 organizations have officially received remotely sensed COMS data. This paper describes how satellite remote sensing has been used for decision-making in Korea, and the evolution of the associated education system. Despite the rapid development of remote sensing, Korea is facing shortcomings in the applicability of remote sensing to industry and society. The two future geostationary satellites planned by the Korean Government, GK (Geo-KOMPSAT)-2A and GK-2B, for monitoring climate and the environment in East Asia from 2018/2019 will alleviate these shortcomings.
- 작성자Choi and Ho
- 작성일2024.08.28
- 조회수73
- 2015
Climatological features of WRF-simulated tropical cyclones over the western North Pacific

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.
- 작성자Kim et al.
- 작성일2024.08.28
- 조회수62
- 2015
A new dynamical index for classification of cold surge types over East Asia

The cold surges over East Asia can be classified into wave-train type and blocking type according to their dynamic origins. In the present study, two dynamic indices are proposed to objectively identify cold surge types using potential temperature (θ) on the dynamic tropopause at 2-potential vorticity units (2-PVU) surface. The two indices are designed to represent primary characteristics of the two types of cold surge. The wave-train index (WI) is defined as a difference of anomalous θ on the 2-PVU surface between the western North Pacific and northeast China, which captures a southward (northward) intrusion of cold (warm) air mass related to the trough-ridge pattern. The blocking index (BI) is defined as a difference of anomalous θ between the subarctic region and northeast China, which indicates air mass overturning related to a reversal of the usual meridional θ gradient commonly observed in the occurrence of blocking type cold surge. Composite analyses based on the distribution of the WI and BI clearly demonstrate the dynamic evolutions of corresponding cold surge types. The wave-train cold surge is associated with a southeastward expansion of the Siberian High and northerly wind near surface, which is caused by growing baroclinic waves. During the blocking cold surge, a geopotential height dipole indicating the subarctic blocking and deepening of East Asian coastal trough induces a southward expansion of the Siberian High and northeasterly wind. Compared to the wave-train type, the blocking cold surge exhibits a longer duration and stronger intensity. In the new framework of these dynamic indices, we can detect a third type of cold surge when both the wave-train and the blocking occur together. In addition, we can exclude the events that do not have the essential features of the upper tropospheric disturbances or the subarctic anticyclonic circulation, which are responsible for cold surge occurrence, using the new indices.
- 작성자Park et al.
- 작성일2024.08.28
- 조회수121
- 2015
Sensitivity of Arctic warming to sea surface temperature distribution over sea-ice melted region in AGCM experiments

Substantial reduction in Arctic sea ice in recent decades has intensified air-sea interaction over the Arctic Ocean and has altered atmospheric states in the Arctic and surrounding high-latitude regions. This study has found that the atmospheric responses related to Arctic sea-ice melt in the cold season (October–March) depend on sea-ice fraction and are very sensitive to in situ sea surface temperature (SST) from a series of atmospheric general circulation model (AGCM) simulations in which multiple combinations of SSTs and sea-ice concentrations are prescribed in the Arctic Ocean. It has been found that the amplitude of surface warming over the melted sea-ice region is controlled by concurrent in situ SST even if these simulations are forced by the same sea-ice concentration. Much of the sensitivity of surface warming to in situ SST are related with large changes in surface heat fluxes such as the outgoing long-wave flux in early winter (October–December) and the sensible and latent heat fluxes for the entire cold season. Vertical extension of surface warming and moistening is sensitive to these changes as well; the associated condensational heating modulates a static stability in the lower troposphere. This study also indicates that changes in SST fields in AGCM simulations must be implemented with extra care, especially in the melted sea-ice region in the Arctic. The statistical method introduced in this study for adjusting SSTs in conjunction with a given sea-ice change can help to model the atmospheric response to sea-ice loss more accurately.
- 작성자Jun et al.
- 작성일2024.08.28
- 조회수70
- 2014
Projected climate regimes shift under future global warming from 4 multi-model, multi-scenarios CMIP5 simulations

This study examined shifts in climate regimes over the global land area using the Köppen–Trewartha (K–T) climate classification by analyzing observations during 1900–2010, and simulations during 1900–2100 from twenty global climate models participating in Phase 5 of the Coupled Model Inter-comparison Project (CMIP5). Under the Intergovernmental Panel on Climate Change Representative Concentration Pathways 8.5 (RCP8.5) scenario, the models projected a 3°–10 °C warming in annual temperature over the global land area by the end of the twenty-first century, with strong (moderate) warming in the high (middle) latitudes of the Northern Hemisphere and weaker warming in the tropics and the Southern Hemisphere. The projected changes in precipitation vary considerably in space and present greater uncertainties among the models. Overall, the models are consistent in projecting increasing precipitation over the high-latitude of the Northern Hemisphere, and reduced precipitation in the Mediterranean, southwestern North America, northern and southern Africa and Australia. Based on the projected changes in temperature and precipitation, the K–T climate types would shift toward warmer and drier climate types from the current climate distribution. Regions of temperate, tropical and dry climate types are projected to expand, while regions of polar, sub-polar and subtropical climate types are projected to contract. The magnitudes of the projected changes are stronger in the RCP8.5 scenario than the low emission scenario RCP4.5. On average, the climate types in 31.4% and 46.3% of the global land area are projected to change by the end of the twenty-first century under RCP4.5 and RCP8.5 scenarios, respectively. Further analysis suggests that changes in precipitation played a slightly more important role in causing shifts of climate type during the twentieth century. However, the projected changes in temperature play an increasingly important role and dominate shifts in climate type when the warming becomes more pronounced in the twenty-first century.
- 작성자Feng et al.
- 작성일2024.08.28
- 조회수57
- 2014
Influence of non-feedback variations of radiation on the determination of climate feedback

Recent studies have estimated the magnitude of climate feedback based on the correlation between time variations in outgoing radiation flux and sea surface temperature (SST). This study investigates the influence of the natural non-feedback variation (noise) of the flux occurring independently of SST on the determination of climate feedback. The observed global monthly radiation flux is used from the Clouds and the Earth's Radiant Energy System (CERES) for the period 2000–2008. In the observations, the time lag correlation of radiation and SST shows a distorted curve with low statistical significance for shortwave radiation while a significant maximum at zero lag for longwave radiation over the tropics. This observational feature is explained by simulations with an idealized energy balance model where we see that the non-feedback variation plays the most significant role in distorting the curve in the lagged correlation graph, thus obscuring the exact value of climate feedback. We also demonstrate that the climate feedback from the tropical longwave radiation in the CERES data is not significantly affected by the noise. We further estimate the standard deviation of radiative forcings (mainly from the noise) relative to that of the non-radiative forcings, i.e., the noise level from the observations and atmosphere–ocean coupled climate model simulations in the framework of the simple model. The estimated noise levels in both CERES (>13 %) and climate models (11–28 %) are found to be far above the critical level (~5 %) that begins to misrepresent climate feedback.
- 작성자Choi et al.
- 작성일2024.08.28
- 조회수68
- 2014