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- Jeong, Jee-Hoon, 1976, et al.
(författare)
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Impact of urban warming on earlier spring flowering in Korea
- 2011
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Ingår i: International Journal of Climatology. - : Wiley. - 1097-0088 .- 0899-8418. ; :31, s. 1488-1497
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Tidskriftsartikel (refereegranskat)abstract
- Using long-term (1954-2004) observations of four selected species in South Korea: goldenbell (Forsythia koreana), azalea (Rhododendron mucronulatum), cherry (Prunus yedoensis), and peach (Prunus persica), the impact of urban warming on spring flowering was investigated. Trends of early spring temperatures and first-flowering dates (FFDs) of the four plants were cross-compared among nine differently urbanized cities. It was clearly observed that urban warming has led to an advance in the timing of first-flowering of several days to weeks during recent decades, while the intrinsic physiology of plants to sense thermal energy has not been changed. The degree of advancement of the FFD was observed to be roughly proportional to degree of urbanization. Moreover, the sensitivity of the FFD to urban warming was estimated to be higher for the shrub species (-9.07 and -6.64 days °C-1 for goldenbell and azalea, respectively) than the tree species (-2.46 and -2.90 days °C-1 for peach and cherry, respectively). Our results suggest that the impact of urban warming should be considered as an influential factor which drives changes in the regional natural environment, especially in regions of rapid urbanization. Copyright © 2010 Royal Meteorological Society
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| 3. |
- JEONG, SJ, et al.
(författare)
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Increase in vegetation greenness and decrease in springtime warming over east Asia
- 2009
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Ingår i: GEOPHYSICAL RESEARCH LETTERS. - 0094-8276. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the impact of increased vegetation greening on the springtime temperature over east Asia for 1982-2000. An analysis of station-based temperature records and satellite-measure normalized difference vegetation index (NDVI) indicates that slight warming (<0.4 degrees C 10-yr(-1)) occurred over regions that experienced large increase in NDVI (>= 0.08 10-yr(-1)). On the contrary, strong warming (>= 0.8 degrees C 10-yr(-1)) occurred over regions that exhibited minor changes in NDVI (<0.04 10-yr(-1)). For the most part, this inverse NDVI-temperature relationship observed with the daily maximum temperature. Thus, it is suggested that the decrease in warming was mostly attributable to the increase in evapotranspiration associated with increased vegetation greening. Earlier vegetation growth may have further strengthened the effect of this vegetation-evaporation on spring temperature. Citation: Jeong, S.-J., C.-H. Ho, and J.-H. Jeong (2009), Increase in vegetation greenness and decrease in springtime warming over east Asia, Geophys. Res. Lett., 36, L02710, doi: 10.1029/2008GL036583.
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| 4. |
- JEONG, SJ, et al.
(författare)
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Potential impact of vegetation feedback on European heat waves in a 2 x CO 2 climate: Vegetation impact on European heat waves
- 2010
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 99:3-4, s. 625-635
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Tidskriftsartikel (refereegranskat)abstract
- Inclusion of the effects of vegetation feedback in a global climate change simulation suggests that the vegetation–climate feedback works to alleviate partially the summer surface warming and the associated heat waves over Europe induced by the increase in atmospheric CO2 concentrations. The projected warming of 4°C over most of Europe with static vegetation has been reduced by 1°C as the dynamic vegetation feedback effects are included.. Examination of the simulated surface energy fluxes suggests that additional greening in the presence of vegetation feedback effects enhances evapotranspiration and precipitation, thereby limiting the warming, particularly in the daily maximum temperature. The greening also tends to reduce the frequency and duration of heat waves. Results in this study strongly suggest that the inclusion of vegetation feedback within climate models is a crucial factor for improving the projection of warm season temperatures and heat waves over Europe
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| 5. |
- JEONG, SJ, et al.
(författare)
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Reduction of spring warming over East Asia associated with vegetation feedback
- 2009
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Ingår i: GEOPHYSICAL RESEARCH LETTERS. - 0094-8276. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- Over East Asia, surface air temperature displays a significant increasing trend particularly in early months of the year for the period of 1982-2000. Warming per decade is strongest in late winter, 1.5 degrees C in February and 1.1 degrees C in March, but is significantly reduced in spring, 0.4 degrees C in April and 0.1 degrees C in May. During the analysis period, the reduced temperature increase from late winter to spring is found to be in contrast with the increased vegetation greenness derived from the satellite-measured leaf area index over the domain. We examined this inverse relationship using two climate model experiments-coupled with and without a dynamic vegetation model. In both experiments, strong warming in winter is relatively well reproduced, but weak warming in spring is observed only in the coupled experiment. Analysis of the surface energy budget indicates that weaker spring warming results from an evaporative cooling effect due to the increased vegetation greenness. Over East Asia, the vegetation-evaporation feedback, therefore, may produce seasonal asymmetry in the warming trend. Citation: Jeong, S.-J., C.-H. Ho, K.-Y. Kim, and J.-H. Jeong (2009), Reduction of spring warming over East Asia associated with vegetation feedback, Geophys. Res. Lett., 36, L18705, doi: 10.1029/2009GL039114.
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| 6. |
- Walther, Alexander, 1976, et al.
(författare)
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Evaluation of the warm season diurnal cycle of precipitation over Sweden simulated by the Rossby Centre regional climate model RCA3
- 2013
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Ingår i: Atmospheric Research. - : Elsevier BV. - 0169-8095. ; 119, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the diurnal cycle of precipitation over Sweden for the warm season (April to September) both in hourly observational data and in simulations from the Rossby Centre regional climate model (RCA3). A series of parallel long-term simulations of RCA3 with different horizontal resolutions - 50, 25, 12, and 6 km - were analyzed to investigate the sensitivity of the model's horizontal resolution to the simulated diurnal cycle of precipitation. Overall, a clear distinction between an afternoon peak for inland stations and an early morning peak for stations along the Eastern coast is commonly found both in observation and model results. However, the diurnal cycle estimated from the model simulations show too early afternoon peaks with too large amplitude compared to the observation. Increasing horizontal model resolution tends to reduce this bias both in peak timing and amplitude, but this resolution effect seems not to be monotonic; this is clearly seen only when comparing coarser resolution results with the 6 km resolution result. As the resolution increases, the peak timing and amplitude of the diurnal cycle of resolved large-scale precipitation become more similar to the observed cycle of total precipitation while the contribution of subgrid scale convective precipitation to the total precipitation decreases. An increase in resolution also tends to reduce too much precipitation of relatively light intensity over inland compared to the observation, which may also contribute to the more realistic simulation of the afternoon peak in convective precipitation. (C) 2011 Elsevier B.V. All rights reserved.
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| 7. |
- Walther, Alexander, 1976, et al.
(författare)
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Potential future changes of the diurnal precipitation properties over Sweden
- 2011
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Ingår i: Geophysical Research Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study we investigate potential future changes of the diurnal rainfall cycle over Sweden in the summer season (AMJJAS). Rainfall extremes are one of the most significant natural hazards related to climate. Precipitation characteristics strongly influence crops, soil properties, run-off and erosion, as well as human infrastructure such as the drainage systems in urban areas. The investigation of sub-daily rainfall records makes it possible to get detailed information about the diurnal precipitation cycle. A high-quality 1-hourly precipitation database covering 13 years of observations from 93 stations is available. In previous studies it could be shown that there is a distinct temporal and spatial pattern of the diurnal rainfall cycle. The performance of the Rossby Centre regional climate model (RCA3) in terms of simulating the observed diurnal cycle was investigated and the simulations quite realistically captured the general characteristics of the diurnal cycle. The diurnal cycle can be characterized by the presence of a peak, its timing and its shape. A higher and narrower peak means higher rainfall intensity on a shorter timescale. In contrast, a flatter and wider peak reflects a smaller temporal diurnal variability and lower rainfall intensity.
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