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Abstract. Several previous studies on tropical cyclone (TC) risk assessment have
attempted to quantify the relationship between TC damage and its elements
(i.e. exposure, vulnerability, and hazard). For hazard parameters, TC
intensity (e.g. central minimum pressure, maximum wind speed) and size
information (e.g. 30 knot radius of the TC) have been widely utilized. Our
risk analysis of 85 TCs that made landfall in South Korea from 1979 to 2010,
however, suggests that a small deviation of the TC track in the west–east
direction (≤250 km, smaller than the average radius of TC) has a more
dominant effect on the extent and distribution of TC damage than TC intensity
or size. This significant track dependency of TC damage exists because the TC
track is responsible for the realization of hazard change from potential to
active. More specifically, although two TCs may have the same intensity and
size, locally experienced rainfall and wind speed can vary according to their
tracks due to topography. These results suggest that track information should
be considered more carefully in assessments of future TC risk.

Póster presentado en: EGU General Assembly 2018 celebrada del 8 al 13 de abril en Viena, Austria. ; The current global climate research has traditionally focused on changes in air temperature and precipitation. As a key climate parameter, changes of winds have a very significant impact on the environment, such as soil wind erosion, air pollution diffusion, wind power energy, etc. In particular, changes of extreme wind speed (i.e., wind gusts) are poorly analyzed and deserve further investigation. In this study we assess trends in máximum wind speed (MWS) across China for 1975-2016, using observed daily wind datasets, and also analyze its relationship with the East Asian monsoon. The raw observed MWS dataset was subject to aquality control and robust homogenization protocol using the Climatol package. The results reveal a statistically significant (p0.10). Even though MWS declines dominated across much of the country through out the year, only as mal number of stations showed statistically significant negative trends in summer (37.7 %) and spring (29.0 %). Our preliminary analyses show that the weakened East Asian monsoon, particularly in winter, positively correlates with the observed changes in MWS. However, statistical significant correlations are too few and further attribution analyses are strongly needed. ; This research is funded by (i) the National Natural Science Foundation of China (Grant No.41621061); (ii) the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant (Grant No. 703733); and (iii) the Swedish Research Council by the project "Detection and attribution of changes in extreme wind gusts over land" (2017-03780).

© 2021. The Authors. ; An observed daily peak wind gusts (DPWG) dataset over Scandinavia, consisting of time series from 127 meteorological stations across Finland, Norway and Sweden, has been created. This dataset provides high-quality and homogenized near-surface DPWG series for Scandinavia, spanning the longest available time period (1996–2016). The aim of this study is to evaluate the ability of two regional climate models (RCMs) in simulating DPWG winds. According to the observed DPWG climatology, meteorological stations are classified into three regions for which wind conditions are influenced by similar physical processes: coast, inland and mountain. Smaller-scale DPWG features of the three regions are only captured when coarser general circulation models or reanalyses are downscaled by a RCM. Dynamic downscaling is thus needed to achieve more realistic simulations of DPWG when compared to their driving models. The performances of the RCMs are found to be more dependent on model dynamics and physics (such as gust parametrization) than on the boundary conditions provided by the driving models. We also found that the RCMs cannot accurately simulate observed DPWG in inland and mountainous areas, suggesting the need for higher horizontal resolution and/or better representation of relevant boundary-layer processes. ; It is supported by Swedish Research Council (2017-03780) and Spanish Ministry of Science, Innovation and Universities (RTI2018-095749-A-I00). C. Azorin-Molina was supported by the Ramon y Cajal fellowship (RYC-2017-22,830). G. F. Zhang was supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP 2019QZKK0606) and the National Natural Science Foundation of China (41621061). S. W. Son was supported by the National Foundation of Korea (NFR) grant funded by the Korean government (MSIT) (NFR2018R1A5A1024958).

Póster presentado en: EMS Annual Meeting - European Conference for Applied Meteorology and Climatology 2018, celebrado en Budapest del 3 al 7 de septiembre de 2018. ; This study analyzes the variability of winter haze days and visibility in the Beijing-Tianjin-Hebei (BTH) region in relation to wind speed changes in the lower troposphere and emissions for 1961-2014. Daily surface meteorological data, NCEP/NCAR atmospheric reanalysis data, and fossil fuel emission data are used in this research. The results reveal a significant increase in winter haze days of +0.8 days decade-1 (p<0.01), and a subsequent decline in visibility of-1.56 km decade-1 (p<0.01). Most interestingly, an accelerated increase in haze days was observed for the last 11-year period (+8.3 days decade-1) of the study (2004-2014). The increase of winter haze occurrence and decrease in visibility are partly attributed to: the significant (p<0.01) declining trend of mean wind speed at the near-surface (-0.19 m s-1 decade-1), 925hPa (-0.23 m s-1 decade-1), and 850hPa (-0.21 m s-1 decade-1); the vertical shear of wind between 1000hPa and 850hPa (-0.07 m s-1 decade-1); and, the declining (dust storm frequency as a proxy,-0.41 days dec-1) surrounding particulate sources and increasing fossil fuel emissions (total carbon emission as a proxy, +4820.6 metric tons dec-1). Specifically, wind speed changes in the lower troposphere explain 41.3% of winter haze days and 71.2% of the visibility variance. These are extended to 51.7% and 81.6% respectively when combined with natural (dust storm frequency) and anthropogenic (fossil fuel emissions) particulate sources. Therefore, the analyses show that wind speed changes in the lower troposphere, together with the varied natural and anthropogenic sources of particulates, play a key role in modulating winter haze and visibility conditions in the BTH area. ; This research is funded by the National Natural Science Foundation of China (Grant No.41621061), and funding from the European Union's Horizon 2020 ...

Póster presentado en: EGU General Assembly 2019 celebrada del 7 al 12 de abril en Viena, Austria. ; The Wind erosion in arid and semi-arid areas is an important global environmental issue, and changes in wind speed trends over time play a key role in wind erosion dynamics. In a warming climate, scientists have recently observed a widespread decline in wind speed, termed "stilling". Here, we apply the Revised Wind Erosion Equation Model (RWEQ) to simulate the variability of wind erosion and quantify the impact of wind speed changes on soil degradation dynamics over the eastern agro-pastoral transitional zone of Northern China (EANC) from 1982 to 2016. Our results show that a significant (i.e., p<0.05) decrease (-0.007 m s-1 year-1) of near-surface wind speed was observed annually, with significant declining trends in spring (-0.010 m s-1 year-1 )and autumn (-0.009 m s-1 year-1). At the same time, wind erosion simulations reveal a negative trend for the annual soil loss from wind erosion (SLWE,-6.20 t hectare-2 year-1 , p<0.05; affecting 99.8% of the study region), with significant declining trends in all seasons, particularly in spring (-3.49 t hectare-2 year-1) and autumn (-1.26 hectare-2 year-1). Further, we isolate the effects of wind variability on wind erosion (SLWED) from 1982 to 2016 by the model variable control method. This shows that wind speed variability strongly weakens wind erosion at-8.14 t hectare-2 year-1 (p<0.05) annually, with the strongest stilling recorded in spring leading to major decreases of wind erosion in spring (-4.77 t hectare-2 year-1 , p<0.05). Meanwhile, the weakest stilling in summer had the opposite influence on wind erosion (+0.40 t hectare-2 year-1 , p<0.10). To summarize, our findings have shown a significant impact of wind stilling on the decline of soil erosion rates in Northern China. ; This research is funded by the National Natural Science Foundation of China (Grant No. 41621061), and funding from the European Union's Horizon 2020 research and innovation ...

This study simultaneously examines wind speed trends at the land–ocean interface, and below–above the trade-wind inversion layer in the Canary Islands and the surrounding Eastern North Atlantic Ocean: a key region for quantifying the variability of trade-winds and its response to large-scale atmospheric circulation changes. Two homogenized data sources are used: (1) observed wind speed from nine land-based stations (1981–2014), including one mountain weather station (Izaña) located above the trade-wind inversion layer; and (2) simulated wind speed from two atmospheric hindcasts over ocean (i.e., SeaWind I at 30 km for 1948–2014; and SeaWind II at 15 km for 1989–2014). The results revealed a widespread significant negative trend of trade-winds over ocean for 1948–2014, whereas no significant trends were detected for 1989–2014. For this recent period wind speed over land and ocean displayed the same multi-decadal variability and a distinct seasonal trend pattern with a strengthening (late spring and summer; significant in May and August) and weakening (winter–spring–autumn; significant in April and September) of trade-winds. Above the inversion layer at Izaña, we found a predominance of significant positive trends, indicating a decoupled variability and opposite wind speed trends when compared to those reported in boundary layer. The analysis of the Trade Wind Index (TWI), the North Atlantic Oscillation Index (NAOI) and the Eastern Atlantic Index (EAI) demonstrated significant correlations with the wind speed variability, revealing that the correlation patterns of the three indices showed a spatio-temporal complementarity in shaping wind speed trends across the Eastern North Atlantic. ; C. A. -M. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 703733 (STILLING project). This research was also supported by the Research Projects: Swedish BECC, MERGE, VR (2014–5320), PCIN-2015-220, CGL2014-52135-C03-01 and Red de ...

Assessing change in daily maximum wind speed and its likely causes is crucial for many applications such as wind power generation and wind disaster risk governance. Multidecadal variability of observed near-surface daily maximum wind speed (DMWS) from 778 stations over China is analyzed for 1975–2016. A robust homogenization protocol using the R package Climatol was applied to the DMWS observations. The homogenized dataset displayed a significant (p 0.10); that is, DMWS declined during the cold semester (October–March) and increased during the warm semester (April–September). Correlation analysis of the Arctic Oscillation, the Southern Oscillation, and the west Pacific modes exhibited significant correlation with DMWS variability, unveiling their complementarity in modulating DMWS. Further, we explored potential physical processes relating to the atmospheric circulation changes and their impacts on DMWS and found that 1) overall weakened horizontal airflow [large-scale mean horizontal pressure gradient (from −0.24 to +0.02 hPa decade−1) and geostrophic wind speed (from −0.6 to +0.6 m s−1 decade−1)], 2) widely decreased atmospheric vertical momentum transport [atmospheric stratification thermal instability (from −3 to +1.5 decade−1) and vertical wind shear (from −0.4 to +0.2 m s−1 decade−1)], and 3) decreased extratropical cyclones frequency (from −0.3 to 0 month decade−1) are likely causes of DMWS change. ; This study was supported by the National Natural Science Foundation of China (Grant 41621061), the National Key Research and Development Program–Global Change and Mitigation Project (Grant 2016YFA0602404), funding from STINT (CH2015-6226), and the European Union's Horizon 2020 research and innovation ...

This study simultaneously examines wind speed trends at the land?ocean interface, and below?above the trade-wind inversion layer in the Canary Islands and the surrounding Eastern North Atlantic Ocean: a key region for quantifying the variability of trade-winds and its response to large-scale atmospheric circulation changes. Two homogenized data sources are used: (1) observed wind speed from nine land-based stations (1981?2014), including one mountain weather station (Izaña) located above the trade-wind inversion layer; and (2) simulated wind speed from two atmospheric hindcasts over ocean (i.e., SeaWind I at 30 km for 1948?2014; and SeaWind II at 15 km for 1989?2014). The results revealed a widespread significant negative trend of trade-winds over ocean for 1948?2014, whereas no significant trends were detected for 1989?2014. For this recent period wind speed over land and ocean displayed the same multi-decadal variability and a distinct seasonal trend pattern with a strengthening (late spring and summer; significant in May and August) and weakening (winter?spring?autumn; significant in April and September) of trade-winds. Above the inversion layer at Izaña, we found a predominance of significant positive trends, indicating a decoupled variability and opposite wind speed trends when compared to those reported in boundary layer. The analysis of the Trade Wind Index (TWI), the North Atlantic Oscillation Index (NAOI) and the Eastern Atlantic Index (EAI) demonstrated significant correlations with the wind speed variability, revealing that the correlation patterns of the three indices showed a spatio-temporal complementarity in shaping wind speed trends across the Eastern North Atlantic. ; C. A. -M. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 703733 (STILLING project). This research was also supported by the Research Projects: Swedish BECC, MERGE, VR (2014–5320), PCIN-2015-220, CGL2014-52135-C03-01 and Red de variabilidad y cambio climático RECLIM (CGL2014-517221-REDT). M.M is indebted to the Spanish Government for funding through the "Ramón y Cajal" program and supported by Grant PORTIO (BIA2015-70644-R)

Wind gusts represent one of the main natural hazards due to their increasing socioeconomic and environmental impacts on, as examples: human safety; maritime-terrestrial-aviation activities; engineering and insurance applications; and energy production. However, the existing scientific studies focused on observed wind gusts are relatively few compared to those on mean wind speed. In Australia, previous studies found a slowdown of near-surface mean wind speed, termed "stilling", but a lack of knowledge on the multi-decadal variability and trends in the magnitude (wind speed maxima) and frequency (exceeding the 90th percentile) of wind gusts exists. A new homogenized daily peak wind gusts (DPWG) dataset containing 548 time series across Australia for the period 1941-2016 is analyzed to determine long-term trends in wind gusts. Here we show that both the magnitude and frequency of DPWG declined across much of the continent, with a distinct seasonality: negative trends in summer-spring-autumn and weak negative or non-trending (even positive) trends in winter. We demonstrate that ocean-atmosphere oscillations such as the Indian Ocean Dipole and the Southern Annular Mode partly modulate decadal-scale variations of DPWG. The long-term declining trend of DPWG is consistent with the "stilling" phenomenon, suggesting that global warming may have reduced Australian wind gusts. ; C.A.M. was supported by Ramon y Cajal fellowship (RYC-2017-22830) and the grants no. VR-2017-03780 and RTI2018-095749-A-I00 (MCIU/AEI/FEDER, UE). G.F.Z was supported by the Second Tibetan Plateau Scientific Expedition and Research Program (No. 2019QZKK0606) and National Natural Science Foundation of China (Grant No. 41621061). S.W.S was partly supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (NRF2018R1A5A1024958).

Presentación realizada para: XI Congreso de la Asociación Española de Climatología celebrado Cartagena entre el 17 y el 19 de octubre de 2018. ; This research has received funding from the European Union's Horizon 2020 research and innovation programmeunder the Marie Skłodowska-Curie grant agreement No. 703733 (STILLING project).

Abstract
Third Pole natural cascade alpine lakes (NCALs) are exceptionally sensitive to climate change, yet the underlying cryosphere-hydrological processes and associated societal impacts are largely unknown. Here, with a state-of-the-art cryosphere-hydrology-lake-dam model, we quantified the notable high-mountain Hoh-Xil NCALs basin (including Lakes Zonag, Kusai, Hedin Noel, and Yanhu, from upstream to downstream) formed by the Lake Zonag outburst in September 2011. We demonstrate that long-term increased precipitation and accelerated ice and snow melting as well as short-term heavy precipitation and earthquake events were responsible for the Lake Zonag outburst; while the permafrost degradation only had a marginal impact on the lake inflows but was crucial to lakeshore stability. The quadrupling of the Lake Yanhu area since 2012 was due to the tripling of inflows (from 0.25 to 0.76 km3/year for 1999 to 2010 and 2012 to 2018, respectively). Prediction of the NCALs changes suggests a high risk of the downstream Qinghai–Tibet Railway, necessitating timely adaptions/mitigations.