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국제학술지

공지 (2025. 10. 28.)

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Enhanced regional terrestrial carbon uptake over Korea revealed by atmospheric CO2 measurements from 1999 to 2017

Abstract: Understanding changes in terrestrial carbon balance is important to improve our knowledge of the regional carbon cycle and climate change. However, evaluating regional changes in the terrestrial carbon balance is challenging due to the lack of surface flux measurements. This study reveals that the terrestrial carbon uptake over the Republic of Korea has been enhanced from 1999 to 2017 by analyzing long-term atmospheric CO2 concentration measurements at the Anmyeondo Station (36.53°N, 126.32°E) located in the western coast. The influence of terrestrial carbon flux on atmospheric CO2 concentrations (ΔCO2) is estimated from the difference of CO2 concentrations that were influenced by the land sector (through easterly winds) and the Yellow Sea sector (through westerly winds). We find a significant trend in ΔCO2 of −4.75 ppm per decade (p < .05) during the vegetation growing season (May through October), suggesting that the regional terrestrial carbon uptake has increased relative to the surrounding ocean areas. Combined analysis with satellite measured normalized difference vegetation index and gross primary production shows that the enhanced carbon uptake is associated with significant nationwide increases in vegetation and its production. Process-based terrestrial model and inverse model simulations estimate that regional terrestrial carbon uptake increases by up to 18.9 and 8.0 Tg C for the study period, accounting for 13.4% and 5.7% of the average annual domestic carbon emissions, respectively. Atmospheric chemical transport model simulations indicate that the enhanced terrestrial carbon sink is the primary reason for the observed ΔCO2 trend rather than anthropogenic emissions and atmospheric circulation changes. Our results highlight the fact that atmospheric CO2 measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle even where anthropogenic emissions are not negligible.
- 작성자Yun et al.
- 작성일2024.08.22
- 조회수63
- 2020
Dominance of large-scale atmospheric circulations in long-term variations of winter PM10 concentrations over East Asia

Abstract: Concentrations of wintertime particulate matters of diameters below 10 μm (PM10) in South Korea and China have decreased since the 2000s largely owing to the emissions reduction policies of the two countries; however, this decreasing tendency has been notably weakened, or even been reversed, in recent years. This study examines the influence of large-scale atmospheric circulations on this PM10 change over East Asia for the winters (December–February) of the 2004/05–2015/16 period using an empirical orthogonal function (EOF) analysis. The first EOF mode, which accounts for 32.7% of the total variance, indicates decreases in PM10 concentrations until 2012 and thereafter increases in them particularly at most stations in eastern and northeastern China. Regression patterns of meteorological variables with respect to the first EOF time series indicate that the wintertime PM10 variations over East Asia are greatly influenced by the Ural blocking; the weakening of the Ural blocking after 2014 led to the weakening of cold air flows from the north and provided atmospheric conditions favorable for bad air quality events over East Asia. The second EOF mode, which accounts for 20.1% of the total variance, shows a similar spatial distribution as the linear trend of PM10 concentrations during the analysis period and would be related to the long-term changes in emissions. Our findings emphasize that the long-term variations in air quality over East Asia are affected primarily by the variations in large-scale atmospheric circulations with secondary contributions from the changes in emissions.
- 작성자Lee et al.
- 작성일2024.08.22
- 조회수69
- 2020
A dipole mode of spring precipitation between southern China and Southeast Asia associated with the eastern and cent...

Abtract: Because spring precipitation in East Asia is critical for recharging water resources after dry winters, its spatiotemporal variations and related mechanisms need in-depth research. This study analyzed a leading spatiotemporal variability of precipitation over East Asia for boreal spring (March-May) during 1979 to 2017. We found that a dipole mode dominates the anomalous spring precipitation between southern China and Southeast Asia with significant interannual and decadal variations. The interannual dipole mode is attributable to the eastern Pacific (EP)-type El Niño-Southern Oscillation (ENSO) while the decadal dipole mode is related to the decadal variation of the central Pacific (CP)-type ENSO. In the El Niño phases of both time scales, the anticyclonic anomaly over the South China Sea and Philippines causes moisture convergence (divergence) over southern China (Southeast Asia), resulting in positive (negative) precipitation anomalies therein; the opposite occurs in the La Niña phases. The ensemble experiments using the Community Atmosphere Model version 5.1 confirmed that the tropical sea surface temperature (SST) in the EP- and CP-type ENSO can be the major drivers of the interannual and decadal dipole modes, respectively. About half of 15 climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5) showed that the El Niño phase of dipole mode will become dominant in the future. The individual models' future projections however considerably vary, implying that there is still large uncertainty. Full title: A dipole mode of spring precipitation between southern China and Southeast Asia associated with the eastern and central Pacific types of ENSO
- 작성자Park et al.
- 작성일2024.08.22
- 조회수230
- 2020
Tropical cyclones and climate change assessment: Part II. Projected response to anthropogenic warming

Abstract: Model projections of tropical cyclone (TC) activity response to anthropogenic warming in climate models are assessed. Observations, theory, and models, with increasing robustness, indicate rising global TC risk for some metrics that are projected to impact multiple regions. A 2°C anthropogenic global warming is projected to impact TC activity as follows. 1) The most confident TC-related projection is that sea level rise accompanying the warming will lead to higher storm inundation levels, assuming all other factors are unchanged. 2) For TC precipitation rates, there is at least medium-to-high confidence in an increase globally, with a median projected increase of 14%, or close to the rate of tropical water vapor increase with warming, at constant relative humidity. 3) For TC intensity, 10 of 11 authors had at least medium-to-high confidence that the global average will increase. The median projected increase in lifetime maximum surface wind speeds is about 5% (range: 1%–10%) in available higher-resolution studies. 4) For the global proportion (as opposed to frequency) of TCs that reach very intense (category 4–5) levels, there is at least medium-to-high confidence in an increase, with a median projected change of +13%. Author opinion was more mixed and confidence levels lower for the following projections: 5) a further poleward expansion of the latitude of maximum TC intensity in the western North Pacific; 6) a decrease of global TC frequency, as projected in most studies; 7) an increase in global very intense TC frequency (category 4–5), seen most prominently in higher-resolution models; and 8) a slowdown in TC translation speed.
- 작성자Knutson et al.
- 작성일2024.08.22
- 조회수60
- 2019
Tropical cyclones and climate change assessment: Part I. Detection and attribution

Abstract: An assessment was made of whether detectable changes in tropical cyclone (TC) activity are identifiable in observations and whether any changes can be attributed to anthropogenic climate change. Overall, historical data suggest detectable TC activity changes in some regions associated with TC track changes, while data quality and quantity issues create greater challenges for analyses based on TC intensity and frequency. A number of specific published conclusions (case studies) about possible detectable anthropogenic influence on TCs were assessed using the conventional approach of preferentially avoiding type I errors (i.e., overstating anthropogenic influence or detection). We conclude there is at least low to medium confidence that the observed poleward migration of the latitude of maximum intensity in the western North Pacific is detectable, or highly unusual compared to expected natural variability. Opinion on the author team was divided on whether any observed TC changes demonstrate discernible anthropogenic influence, or whether any other observed changes represent detectable changes. The issue was then reframed by assessing evidence for detectable anthropogenic influence while seeking to reduce the chance of type II errors (i.e., missing or understating anthropogenic influence or detection). For this purpose, we used a much weaker “balance of evidence” criterion for assessment. This leads to a number of more speculative TC detection and/or attribution statements, which we recognize have substantial potential for being false alarms (i.e., overstating anthropogenic influence or detection) but which may be useful for risk assessment. Several examples of these alternative statements, derived using this approach, are presented in the report.
- 작성자Knutson et al.
- 작성일2024.08.22
- 조회수80
- 2019
Tropical cyclone rainfall in the Mekong River basin for 1983–2016

Abstract: As home to about 70 million people, the Mekong River Basin (MRB), located in Mainland Southeast Asia, is often influenced by tropical cyclones (TCs) landfalling. The TCs not only cause flood and storm hazards, but also play important roles in providing freshwater resource and welcomed sediment transports. Our study focuses on the climatology of TCs and associated rainfall (TCR) in the MRB for 1983–2016. Results show that: (i) the mean landfall occurrence of TCs is 6.2 yr-1, leading to 36.7 mm yr-1 of annual mean TCR (2.5% of the annual total precipitation), which mainly occur in monsoon-TC season (i.e., June–November); (ii) TCs highly concentrate on the lower eastern MRB, generating the largest TCR contribution of 12.4% to the annual total precipitation; (iii) the annual mean contribution of TCs induced extreme precipitation - R20mm and R50mm (days of heavy precipitation rate ≥20 mm day-1 and ≥50 mm day-1, respectively) - to that from annual total precipitation is large in the lower eastern MRB; (iv) over 60% of the basin area is influenced by TCR on average; and (v) a significant weakening trend of the TC frequency has been observed. The present findings lay a foundation for further in-depth research of the potential influence of the dynamic TCs and the associated rainfall in the MRB.
- 작성자Chen et al.
- 작성일2024.08.22
- 조회수69
- 2019
TC as a possible remote controller of air quality over the Republic of Korea through poleward propagating Rossby waves

Abstract: Air quality depends as much on large-scale tropospheric circulation as on the amount of pollutant emissions. Many studies have found a relationship between air quality and midlatitude synoptic weather systems. A stable low-level troposphere and airflow from polluted areas are conditions that favor air pollution in a region. However, few studies have focused on the possible remote effect of tropical cyclone (TC) activity in the tropics on air quality in the midlatitude East Asian countries. Here, we found that TCs in the South China Sea (SCS) can increase the concentration of particulate matter with aerodynamic diameters less than 10 μm (PM10) over South Korea through poleward-propagating Rossby waves. According to our analyses, intense divergence due to a TC causes a barotropic Rossby wave train from the SCS to the North Pacific Ocean. Anomalous highs over the Korean Peninsula (part of the Rossby wave train) result in stable air conditions and cause polluted air inflow to increase the PM10 concentration up to 65 μg m-3. Our finding suggests that TC activity in the tropics should be considered for more accurate forecasts of air quality in South Korea. Full title: Tropical Cyclone as a possible remote controller of air quality over the Republic of Korea through poleward propagating Rossby waves
- 작성자Park et al.
- 작성일2024.08.22
- 조회수59
- 2019
The tropical transition in the western North Pacific: The case of tropical cyclone Peipah (2007)

Abstract: This study examines the transition of an extratropical disturbance to a tropical cyclone (TC), Peipah (2007), in the western North Pacific (WNP), using reanalysis and geostationary satellite data. Instead of regular diurnal fluctuations of deep convection, the pre-TC disturbance accompanies deep convection only for short durations every other day. When the pre-TC vorticity is traced back to 7 days prior to its formation, the traced-back vorticity indicates a strong potential vorticity (PV) trough in the subtropical upper troposphere that originated from the midlatitude lower stratosphere. The quasi-geostrophic forcing and reduced static stability at the leading edge of the PV trough result in the formation of an extratropical disturbance. The vertical structure of the extratropical disturbance shows maximum vorticity in the upper troposphere and cold temperature anomaly within it throughout the entire troposphere. As the extratropical disturbance moved into the tropical WNP, deep convection associated with quasi-geostrophic dynamics over the warm ocean initiated tropical transition of the extratropical disturbance to a TC through diabatic redistribution of PV in the tropospheric column as well as transition of the cold anomaly into a warm anomaly within the vortex. With additional contribution of barotropic energy conversion in the lower troposphere, the warm-core low system finally developed into a TC-strength vortex. These results indicate that PV troughs of the stratospheric origin over the subtropical Pacific Ocean can contribute to TC formations in the WNP.
- 작성자Chang et al.
- 작성일2024.08.22
- 조회수63
- 2019
Possible link between Arctic Sea ice and January PM10 concentrations in South Korea

Abstract: In this study, we investigated the possible teleconnection between PM10 concentrations in South Korea and Arctic Sea ice concentrations at inter-annual time scales using observed PM10 data from South Korea, NCEP R2 data, and NOAA Sea Ice Concentration (SIC) data from 2001 to 2018. From the empirical orthogonal function (EOF) analysis, we found that the first mode (TC1) was a large-scale mode for PM10 in South Korea and explained about 27.4% of the total variability. Interestingly, the TC1 is more dominantly influenced by the horizontal ventilation effect than the vertical atmospheric stability effect. The pollution potential index (PPI), which is defined by the weighted average of the two ventilation effects, is highly correlated with the TC1 of PM10 at a correlation coefficient of 0.75, indicating that the PPI is a good measure for PM10 in South Korea at inter-annual time scales. Regression maps show that the decrease of SIC over the Barents Sea is significantly correlated with weakening of high pressure over the Ural mountain range region, the anomalous high pressure at 500 hPa over the Korean peninsula, and the weakening of the Siberian High and Aleutian low. Moreover, these patterns are similar to the correlation pattern with the PPI, suggesting that the variability of SIC over the Barents Sea may play an important role in modulating the variability of PM10 in South Korea through teleconnection from the Barents Sea to the Korean peninsula via Eurasia.
- 작성자Kim et al.
- 작성일2024.08.22
- 조회수62
- 2019
Near-future tropical cyclone predictions in the western North Pacific: Fewer tropical storms but more typhoons

Abstract: This study presents forecasts of near-future tropical cyclone (TC) activities over the western North Pacific (WNP) using a TC track-pattern-based prediction model in conjunction with long-term free-run simulations from the National Centers for Environmental Prediction Climate Forecast System. The prediction shows that the East Asian coastal area will be affected by fewer TC landfalls. However, the number of stronger TC landfalls may increase in the near future (2016–2030) com pared to the present-day period (2002–2015). The potential candidates for modulating the near-future TC activity are three large-scale climate variability: El Niño–Southern Oscillation (ENSO), the North Pacific sea surface temperature (NPSST) variation, and basin-wide warming of the Pacific. More frequent El Niño episodes in the near future may contribute to the activation of TC formations in the far-eastern tropical ocean, which generates a favorable influence on TC intensification due to longer distances and development periods over the ocean. NPSST variations have contrasting effects, i.e., they have unfavorable effects on TC genesis due to weak vorticity, while creating favorable conditions for TC intensification by pro viding more humid environments in the subtropics. The impact of overall Pacific warming on the changes in TC activities is low compared to that of the other two factors. Our results physically demonstrate the contributions of three WNP sea surface temperature variability on near-future TC activity, emphasizing the critical roles of ENSO and NPSST rather than the near-term warming effect.
- 작성자Choi et al.
- 작성일2024.08.22
- 조회수67
- 2019
Influence of vertical wind shear on wind- and rainfall areas of tropical cyclones making landfall over South Korea

Abstract: The wind- and rainfall areas of tropical cyclones (TCs) making landfall over South Korea were examined for the period 1998–2013 by using the Modern Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) and Tropical Rainfall Measuring Mission (TRMM) 3B42 data. Here, the wind- and rainfall areas were defined as the regions where wind speeds and precipitation rates exceed 14 m s-1 and 80 mm day-1 within 1000 km from the TC center, respectively. In general, TCs show significantly asymmetric wind and rainfall structures, with strong vertical wind shear appearing over South Korea during the landfall period. The rainfall area significantly increases with environmental vertical wind shear while the wind area is not sensitive to it. Composite analyses of the cases of strong and weak vertical wind shear confirm that the increase of rainfall area is related to the asymmetric convection (rising/sinking motion in the downshear-left/upshear-right side) induced by the vertical wind shear. This work highlights the importance of local atmospheric environment in determining the area primarily affected by strong winds or heavy rainfall during TC landfalls.
- 작성자Kim et al.
- 작성일2024.08.22
- 조회수67
- 2019
Impact of urbanization on spring and autumn vegetation phenology in the Seoul capital area, South Korea

Abstract: Urbanization exerts anthropogenic forcing that affects regional climate and ecosystems. With increasing levels of urbanization associated with urban population growth in the near future, understanding of the impact of urbanization on terrestrial ecosystems is important for predicting future environmental changes. This study evaluates the impact of urbanization on spring and autumn phenology by addressing the relationship between population density and phenology at nine stations in the Seoul Capital Area (SCA), South Korea during 1991–2010. We analyze the spring budburst dates for the six species (Prunus mume, Forsythia koreana, Rhododendron mucronulatum, Prunus yedoensis, Prunus persica, and Prunus pyrifolia) and the leaf coloring date for the two species (Ginkgo biloba and Acer palmatum). Regardless of species, the density of the urban population shows significant negative (positive) relationships with spring (autumn) phenology. In the SCA, urban population increases are related to earlier spring budburst up to 13 days and delayed leaf coloring up to 15 days. The most apparent spring budburst sensitivity is observed in Prunus mume, whereas the most dominant autumn leaf coloring sensitivity is observed in Acer palmatum. The relationship between population density and phenology is supported by the difference in nocturnal temperatures between stations which varies with the population density. Our results suggest that, in addition to global warming, future population growth should be considered in ecosystem assessments of human-induced environmental changes.
- 작성자Jeong et al.
- 작성일2024.08.22
- 조회수74
- 2019
Urbanization may reduce the risk of frost damage to spring flowers: A case study of two shrub species in South Korea

Abstract: Regional warming, owing to urbanization, leads to earlier spring phenological events and may expose plants to hard freeze damage. This study examined the influence of urbanization on the risk of frost damage to spring flowers in South Korea from 1973 to 2015. For the analysis period, we categorized 25 cities into two groups: those showing rapid population growth (rPG) ≥ 200,000, including 13 cities, and those showing no or decreased population growth (nPG), including 12 cities. We then investigated the time from the last frost dates (LFDs) in spring to the first flowering dates (FFDs) for each group. The rPG group experienced significant spring warming of 0.47°C per decade, resulting in earlier LFDs and FFDs. For this group, the advancement of LFD was more rapid than that of FFD, and the days between these two dates increased from 0.42 to 0.47 days per decade, implying a reduced risk of frost damage. Spring warming and the advancement of FFDs and LFDs were relatively small for the nPG group, and the LFDs were rather delayed. Consequently, the days between LFDs and FFDs were reduced from −1.05 to −1.67 days per decade, indicating an increased risk of frost damage. The contrasting changes in the frost-damage risk between the two city groups can be attributed to distinct urban warming at night, which makes the LFDs substantially earlier in the rPG group. Therefore, this study suggests that the warming associated with urbanization may lessen the risk of spring frost damage to plants in rapidly growing urban areas.
- 작성자Gim et al.
- 작성일2024.08.22
- 조회수73
- 2018
Tropical cyclone signals on rainfall distribution during strong vs. weak Changma/Baiu years

Abstract: The spatiotemporal distribution of summer rainfall is diverse in origin, namely tropical cyclones (TCs) and quasi-stationary monsoon frontal systems. Here, the contribution of TCs to summer rainfall is singled out for the years of strong vs. weak Changma/Baiu, which is represented by the leading mode of the variability in total rainfall over East Asia (20°–45°N, 105°–150°E) during the summers (July and August) of 1979–2014. Analyzing rain gauge based rainfall and TC best track data indicates that the difference in TC-induced rainfall between strong and weak Changma/Baiu years exhibits distinctive subseasonal evolution from that in non-TC-induced rainfall. A deficit in TC-induced rainfall is mainly observed over eastern China and Taiwan, where a surplus in non-TC-induced rainfall exists. This opposite relationship between the difference in TC-induced and non-TC-induced rainfalls, which is associated with westward extensions of the subtropical high and associated westerlies over the East China Sea, implies that the variations of TC-induced rainfall and non-TC-induced rainfall partly offset each other in certain regions of East Asia. For heavy rainfall (> 50 mm day-1), similar features are observed in the whole East Asia region. The variability of total heavy rainfall is dominated by non-TC-induced rainfall, except for the Yangtze River Valley where the variability of TC-induced rainfall cancels out that of non-TC-induced rainfall.
- 작성자Cheung et al.
- 작성일2024.08.22
- 조회수77
- 2018
The relationship between tropical cyclone rainfall area and environmental conditions over the subtropical oceans

Abstract: In this study, the variation of tropical cyclone (TC) rainfall area over the subtropical oceans is investigated using the Tropical Rainfall Measuring Mission precipitation data collected from 1998 to 2014, with a focus on its relationship with environmental conditions. In the subtropics, higher moving speed and larger vertical wind shear significantly contribute to an increase in TC rainfall area by making horizontal rainfall distribution more asymmetric, while sea surface temperature rarely affects the fluctuation of TC rainfall area. This relationship between TC rainfall area and environmental conditions in the subtropics is almost opposite to that in the tropics. It is suggested that, in the subtropics, unlike the tropics, dynamic environmental conditions are likely more crucial to varying TC rainfall area than thermodynamic environmental ones.
- 작성자Kim et al.
- 작성일2024.08.22
- 조회수74
- 2018
Slowdown of spring green-up advancements in boreal forests

Abstract: There is a consensus that the spring phenology of deciduous forests is advancing in response to global warming. Since the late 1990s, however, this tendency of spring phenology advancement has been weakened in over 60% of boreal forests, particularly in Siberia (−0.58 day yr-1 for 1982–1997 vs. −0.17 day yr-1 for 1982–2013) and northwestern North America (NWNA; −0.42 day yr-1 for 1982–1997 vs. 0.07 day yr-1 for 1982–2013). This study investigated the major factor in the weakening trends in the advancement of the start of the growing season (SOS) based on the satellite-observed normalized difference vegetation index (NDVI) in two regions by quantifying the effects of four climatic fields—winter duration (WD; the number of freezing days), pre-season temperature (PT; accumulated temperature from late winter to early spring), green-up temperature (GT; accumulated temperature around the green-up date), and pre-season precipitation (PR; accumulated precipitation before the green-up date)—on changes in the spring green-up trend. The GT explained the majority of the slowdown in the SOS trends in recent decades. In Siberia, the GT increases contributed to the advancement of the SOS during the 1980s and 1990s; however, the GT increase reduced to less than half of these periods resulting in a slowdown of the SOS advancing trend since the early 2000s. In NWNA, GT increases and WD shortening drove the SOS advancement until the late 1990s; however, both effects have been diminished to near zero to result in no further SOS advancements. This study demonstrates that the recent slowdown of the SOS advancing trends over Siberia and NWNA was largely attributed to the weakening of the warming trends, rather than the sensitivity changes of spring phenology to climate variables. This study suggests that the natural climate variability strongly affects the decadal variations in the boreal forest spring phenology.
- 작성자Park et al.
- 작성일2024.08.22
- 조회수69
- 2018
Slow decreasing tendency of fine particles compared to coarse particles associated with recent hot summers in Seoul...

Abstract: In Seoul, South Korea, particulate matters (PMs) significantly decreased for the period 2005–2015 in concert with the implementation of air pollution reduction policies. This study reveals that PM with a diameter smaller than 2.5 μm (PM2.5) has a slower decreasing tendency than PM in the 2.5–10-μm range (PM2.5-10) during summer and that this discrepancy is attributable to the large increase in the summer surface air temperature for the analysis period (0.13°C year-1). During the daytime, especially in the afternoon when the hourly surface air temperature and its increasing rate are high, the difference between the decreasing rates of PM2.5 and PM2.5-10 is pronounced. The slower decrease in PM2.5 compared to PM2.5-10 likely results from the secondary PM2.5 formation being accelerated by the increase in the surface air temperature. Other atmospheric variables that can affect concentrations of PMs, such as insolation, relative humidity, precipitation, wind speed, and sea-level pressure, do not show a meaningful relationship with the discrepancy in the decreasing tendency between the two PMs. Our finding emphasizes the necessity of continuous monitoring and analysis of long-term variability in concentrations of PMs and related meteorological conditions, and the independent establishment of reduction policies for PM2.5 and PM2.5-10 to prepare for anthropogenic climate change and the subsequent air quality change. Full title: Slow decreasing tendency of fine particles compared to coarse particles associated with recent hot summers in Seoul, Korea
- 작성자Lee et al.
- 작성일2024.08.22
- 조회수57
- 2018
Possible relationship of weakened Aleutian Low and air quality improvement in Seoul, South Korea

Abstract: Cold-season air quality in Seoul, South Korea, has been improved noticeably between 2001 and 2015 with a near-50% decrease in the mean concentration of particulate matter with aerodynamic diameters ≤10 μm (PM10). Like the change in mean concentration, the occurrence frequency and intensity of the extreme-high-PM10 episodes exceeding 100 μg m-3 has significantly decreased as well. In addition to the multilateral efforts of the South Korean government to reduce air pollutant emissions, this study proposes that large-scale circulation changes also could have contributed to the air quality improvements. Specifically, the recent weakening of the Aleutian low may have intensified the tropospheric westerlies around the Korean Peninsula, resulting in a shorter residence time of particulate matter over South Korea. Thus, despite constant governmental effort to reduce pollutant emissions, the improvement in air quality over South Korea may be delayed if the Aleutian low recovers its past strength in the future. This study emphasizes the importance of the meteorological field in determining the air quality over South Korea.
- 작성자Oh et al.
- 작성일2024.08.22
- 조회수63
- 2018
Keeping global warming within 1.5 °C constrains emergence of aridification

Abstract: Aridity—the ratio of atmospheric water supply (precipitation; P) to demand (potential evapotranspiration; PET)—is projected to decrease (that is, areas will become drier) as a consequence of anthropogenic climate change, exacerbating land degradation and desertification. However, the timing of significant aridification relative to natural variability—defined here as the time of emergence for aridification (ToEA)—is unknown, despite its importance in designing and implementing mitigation policies. Here we estimate ToEA from projections of 27 global climate models (GCMs) under representative concentration pathways (RCPs) RCP4.5 and RCP8.5, and in doing so, identify where emergence occurs before global mean warming reaches 1.5 °C and 2 °C above the pre-industrial level. On the basis of the ensemble median ToEA for each grid cell, aridification emerges over 32% (RCP4.5) and 24% (RCP8.5) of the total land surface before the ensemble median of global mean temperature change reaches 2 °C in each scenario. Moreover, ToEA is avoided in about two-thirds of the above regions if the maximum global warming level is limited to 1.5 °C. Early action for accomplishing the 1.5 °C temperature goal can therefore markedly reduce the likelihood that large regions will face substantial aridification and related impacts.
- 작성자Park et al.
- 작성일2024.08.22
- 조회수69
- 2018
Influence of winter precipitation on spring phenology in boreal forests

Abstract: Understanding the variations in spring vegetation phenology associated with preseason climate conditions can significantly improve our knowledge on ecosystem dynamics and biosphere–atmosphere interactions. Recent studies have shown that wet winters can delay the start date of the vegetation growing season (SOS) in the high latitudes. However, associated underlying mechanisms remain unclear due to the lack of observation sites as well as complex interactions between various climate and ecosystem variables. In this study, the impact of winter precipitation on year-to-year variations of the SOS in boreal forests from 1982 to 2005 was investigated. Two experiments were performed using the Community Land Model version 4.5. In the control experiment, observed precipitation was used; in the sensitivity experiment, precipitation in the year 1982 was repeated throughout the period. The SOS in the control experiment shows high temporal correlations with the SOS estimated from the satellite-retrieved leaf area index, indicating that the land model is capable of simulating realistic response of vegetation to interannual climate variability. The effects of winter precipitation on the SOS are examined by comparing the two model experiments for wet- and dry winters. After wet winters, the SOS was delayed by 2.7 days over 70.1% of the boreal forests than after dry winters; this accounts for 42.5% of the interannual variation in the SOS. The SOS delay is related to the decrease in the growing degree-days (GDD) based on soil temperatures, suggesting that the effects of heat exposure on vegetation growth is strongly modulated by winter precipitation. The GDD decrease is related to both the increase in snowmelt heat flux and reduced absorption of solar radiation, which are proportional to the amount of winter precipitation and the ratio of short plants to tall trees, respectively. Our results provide a physical basis for the winter precipitation–SOS relationship, suggesting that an increase in winter precipitation can alleviate strong advancing trends in spring vegetation growth in conjunction with global warming even for temperature-limited ecosystems.
- 작성자Yun et al.
- 작성일2024.08.22
- 조회수52
- 2018