The anthropogenic acceleration and intensification of flash drought over the southeastern coastal region of China will continue into the future          下载免费PDF全文

Yumiao Wang  Xing Yuan 《大气和海洋科学快报》2022,15(5):100262

The frequent and rapid onset of flash drought poses a serious threat to agriculture and ecosystems. Detecting human influences on flash droughts and estimating their future risks under climate change have attracted great attention. Focusing on a record-breaking flash drought event in the southeastern coastal region of China in summer 2020, the authors found that the suppression of convective precipitation and high temperature caused by the persistent high geopotential height anomalies and land–atmosphere dry coupling were important reasons for the rapid onset and strong intensity of the flash drought. Event attribution analysis with the latest CMIP6 data showed that anthropogenic climate change has not only increased the likelihood of an onset speed and intensity like those of the 2020 flash drought event, by about 93% ± 20% and 18% ± 15%, respectively, but also increased the chance of their simultaneous occurrence, by about 86% ± 38%, according to their joint probability distribution. Under a business-as-usual future scenario (SSP2-4.5), the likelihood of such an onset speed, intensity, and their simultaneous occurrence will further increase, by 85% ± 33%, 49% ± 8%, and 81% ± 48%, respectively, as compared with current climate conditions. This study highlights the importance of anthropogenic climate change for accelerating and intensifying flash drought in the southeastern coastal region of China.摘要快速爆发的骤旱对农业生产, 生态环境等造成严重威胁, 亟须量化当前及未来气候变化对骤旱爆发过程的影响. 2020年夏季, 在持续高压异常和陆气干耦合的控制下, 我国东南沿海地区出现高温少雨天气并引发极端骤旱事件. 基于第六次国际耦合模式比较计划 (CMIP6) 数据开展归因分析, 本文发现相比天然情景, 温室气体排放等人为因子导致的气候变化不仅使类似2020年骤旱爆发速度和强度的发生概率分别增加93%和18%, 还使其联合概率增加86%. 在目前排放水平下, 此类骤旱爆发速度和强度发生概率及其联合概率在21世纪末将提高85%, 49%, 和81%, 极大增加了干旱适应的挑战.  相似文献   

Sensitivity analysis of planetary boundary layer schemes using the WRF model in Northern Colombia during 2016 dry season     

《Dynamics of Atmospheres and Oceans》2021

This study conducted meteorological simulations in northern Colombia by analyzing different planetary boundary layer (PBL) schemes available in the numerical Weather Research and Forecasting (WRF) model. The study area included three nested domains with horizontal resolutions of 18 km, 6 km, and 2 km, with 38 vertical levels. The evolution and structure of the PBL were analyzed during the driest months (March, April, and May 2016) and in regions with the highest particulate matter concentrations. Sensitivity analysis of the WRF model was performed with two local and two non-local PBL schemes. The results were validated using observations of the surface air temperature, relative humidity, and surface wind speed collected from three meteorological stations in the area. The PBL heights were experimentally determined using radiosonde data provided by a station located in the center of the study area. Variations in PBL heights were estimated using linear regression methods and minimization of statistical errors for the bulk Richardson number, as well as analysis of vertical temperature and wind profiles. The WRF model reliably reproduced the daily values and diurnal cycles of temperature, relative humidity, and wind speed within the PBL and accounted for the influence of topography and sea breezes. Horizontal heat advection dominates the upwelling of air masses when sea breezes are active. The onshore wind direction starts to change from east to northwest, implying a decay in the land breeze regime. All schemes overestimate the mixing height and tend to underestimate surface air temperature values at night. All show wetter conditions and underestimate wind speed. Although the non-local Yonsei University (YSU) scheme shows the best performance, it also shows the largest sources of errors when determining the behavior of the surface layer during stable conditions. Relative humidity and wind speed estimates provided by the local Mellor‐Yamada‐Nakanishi‐Niino (MYNN) scheme were closer to those recorded at the meteorological stations.  相似文献   

An Observational Study on the Local Climate Effect of the Shangyi Wind Farm in Hebei Province     

Yonghong LIU  Bing DANG  Yongming XU  Fuzhong WENG 《大气科学进展》2021,38(11):1905-1919

Zhangjiakou is an important wind power base in Hebei Province, China. The impact of its wind farms on the local climate is controversial. Based on long-term meteorological data from 1981 to 2018, we investigated the effects of the Shangyi Wind Farm (SWF) in Zhangjiakou on air temperature, wind speed, relative humidity, and precipitation using the anomaly or ratio method between the impacted weather station and the non-impacted background weather station. The influence of the SWF on land surface temperature (LST) and evapotranspiration (ET) using MODIS satellite data from 2003 to 2018 was also explored. The results showed that the SWF had an atmospheric warming effect at night especially in summer and autumn (up to 0.95°C). The daytime air temperature changes were marginal, and their signs were varying depending on the season. The annual mean wind speed decreased by 6％, mainly noted in spring and winter (up to 14％). The precipitation and relative humidity were not affected by the SWF. There was no increase in LST in the SWF perhaps due to the increased vegetation coverage unrelated to the wind farms, which canceled out the wind farm-induced land surface warming and also resulted in an increase in ET. The results showed that the impact of wind farms on the local climate was significant, while their impact on the regional climate was slight.  相似文献   

1981—2020年安徽省不同重现期最大风速和极大风速时空变化特征     

李丽  王业斌  鲁俊  王晓东  吴萍  陶寅 《热带气象学报》2022,38(5):662-670

分别从质量控制级别、有效数据完整率、是否均一等方面考虑,选取安徽省51个气象站1981—2020年逐日10 min最大风速和2006—2020年逐日极大风速资料,基于最大风速资料应用阵风系数法构建1981—2005年极大风速,得到1981—2020年极大风速的长时间序列数据;对风速资料进行拟合适度检验,估算了安徽省不同重现期最大风速和极大风速的时间变化以及空间分布,并对极大风速序列延长前后重现期估算情况进行了对比。结果表明:(1) 利用阵风系数法构建的极大风速数据可信,可为因缺少长时间序列的极大风速观测而无法进行50年或者更长重现期估算提供参考;(2) 1981—2020年安徽省历年最大风速强度为12.38 m/s,极大风速强度为20.55 m/s,均为皖南低矮山区的风速值较低,沿江西部及江淮之间中部处于相对大值区;(3) 30年重现期最大风速为12.09~27.23 m/s,50年为12.64~29.01 m/s,均是石台站最小,桐城站最大;30年重现期的极大风速为23.51~39.56 m/s,50年为24.58~41.93 m/s,均为池州站最小,桐城站最大;(4) 短期的观测资料会降低重现期估算结果的可靠性。   相似文献   

渤海冷空气大风过程中3次风速波动的原因分析     

黄彬  杨超  朱男男  易笑园  魏晓琳 《气象科技》2017,45(3):499-507

根据FY-2G卫星遥感监测资料、常规气象观测资料和NCEP逐6h1°×1°再分析资料,分析2014年12月31日至2015年1月1日渤海大风过程中风速的3次波动特征以及影响系统,并对大风期间物理量进行了诊断分析,揭示了冷空气影响过程中渤海大风的突增以及波动性成因。结果表明:当冷空气影响渤海时,冷暖空气对比使低空锋区迅速加强,风力突增明显。大风期间高层深厚的冷平流自上而下形成了一条西北东南向后倾式的冷平流传输通道,平流分3次传送到底层对应着大风期间的3次波动峰值。整个过程动量下传起了重要的作用,下沉气流的径向度越大,高层下沉运动越强,对应地面的风速越大。  相似文献   

基于北斗反射信号的支持向量回归机海面风速反演研究     

涂满红  曹云昌  康金侠 《气象与环境科学》2017,40(2):60-65

随着全球导航卫星系统的发展,一种基于导航卫星反射信号(GNSS-R)的海洋遥感技术成为近年来研究的热点。为研究GNSS-R测风方法,分析了海面风速与反射信号时延功率之间的关系,同时结合机器学习方法中的支持向量回归机方法,将反射信号时延功率作为训练标签,最终完成海面风速的反演。将"北斗反射信号海风海浪探测系统——山东示范站"项目期间海风海浪系统的探测结果与同期风速仪探测结果进行对比分析,结果表明,两者具有很好的一致性,海面风速的反演精度为2.4 m/s,证明了基于北斗反射信号的支持向量回归机海面测风方法是可行的。  相似文献   

More intensive summer tropical cyclone near 30°N of East Asia     

《Dynamics of Atmospheres and Oceans》2017

The present study revealed that a climate regime shift occurred during the 1988–1991 period involving changes in tropical cyclone (TC) intensity (central pressure, maximum sustained wind speed) during the summer near 30°N in East Asia. Climatologically, TC intensity at 110°–125°E near 30°N (over Mainland China) is the weakest at that latitude while the strongest is found at 125°–130°E (over Korea). The TC intensity during the 1991–2015 (91–15) period had strengthened significantly compared to that of the 1965–1988 (65–88) period. The strengthening was due to a significantly lower frequency of TCs that passed through Mainland China during the 91–15 period. This lower frequency of was due to anomalous northeasterlies blown from the anomalous anticyclonic circulation located over continental East Asia and that had strengthened along the coast. Instead, TCs mainly followed a path from eastern regions in the subtropical western North Pacific to Korea and Japan via the East China Sea due to anomalous cyclonic circulations that had strengthened in the western North Pacific. In addition, low vertical wind shear had formed along the mid-latitude region in East Asia and along the main TC track in the 91–15 period, and most regions in the western North Pacific experienced a higher sea surface temperature state during the 91–15 period than in the previous period, indicating that a favorable environment had formed to maintain strong intensities of TCs at the mid–latitudes. The characteristics of TCs at the lower latitudes caused a strong TC intensity at the time of landfall in Korea and a gradual shifting trend of landing location from the western to southern coast in recent years.  相似文献   

基于交叉极化数据的海面风速反演研究     

许遐祯  韩冰  黄敬峰  李正泉  龚强  王秀珍 《气象科学》2017,37(5):629-638

全极化数据可以获取比单极化数据更多的目标信息,研究发现C波段交叉极化数据同样可用于海面风速反演。针对RADARSAT-2 Fine Quad模式具有全极化成像的特点,以我国东部海域为研究区,结合同极化数据和交叉极化数据反演海面风速模型,探究各种极化数据的最优风速反演方法。对于同极化数据采用地球物理模型函数(GMF)和极化率模型(PR)组合的方式进行海面风速反演,对交叉极化数据采用C波段交叉极化海面散射模型(C-2PO)进行海面风速反演,反演结果与ERA-Interim风场数据进行比较分析;此外,对Scan SAR模式交叉极化数据的后向散射系数与海面风速的关系进行探索分析。研究结果表明,RADARSAT-2 Fine Quad模式四种极化数据选用合适的模型均可反演出高精度的海面风速,其中VH和HV极化数据的反演结果基本相同,交叉极化数据反演风速效果好于同极化数据,同时,Scan SAR模式交叉极化数据的后向散射系数随海面风速的增大表现出一定的线性变化趋势。全极化模式数据在海面风速反演上表现出比单极化模式数据较为明显的优势,将成为未来海面风速反演的发展方向。  相似文献   

基于Buckingham模型和Biot-Stoll模型的南沙海域沉积物声速分布特征   总被引：1，自引：0，他引：1  

王景强  郭常升  刘保华  陈文景  侯正瑜  韩国忠 《地球学报》2016,37(3):359-367

为了选择合理的南海南部海底沉积物的声速反演模型,分别利用Wood方程、Buckingham模型、Biot-Stoll模型等声波传播理论模型计算了沉积物的纵波声速,结合沉积物实测声速和物理参数等,对比了模型计算声速与实测声速的变化特征。声速实测值与模型计算值的对比表明,Buckingham模型计算值与实测值的平均偏差最小。研究区实测声速比和模型计算声速比的分布表明,声速的变化特征与沉积环境具有相关性,声速模型计算值与实测值具有相似的变化特征;模型计算声速与实测声速的垂向变化规律不相同,模型计算声速随深度基本不变,而实测声速在陆架、陆坡和海槽等沉积环境中呈现出多种垂向分布特征。研究结果认为,侧重于沉积物孔隙性的Biot-Stoll理论仅适用于陆架区粗颗粒沉积物,兼具流体和弹性固体双重性质的Buckingham理论具有更广的适用范围。该研究对获取南海南部海域沉积物声速分布特征有重要意义,可为多波束测深或浅地层精细解释等提供基础资料。  相似文献   

我国近海洋面10 m风速集合预报客观订正方   总被引：1，自引：0，他引：1  

胡海川  黄彬  魏晓琳 《气象》2017,43(7):856-862

利用2013—2015年ECMWF集合预报10 m风场及我国沿岸和近海88个代表站点风速实况观测,建立基于ECMWF集合预报众数的我国近海洋面10 m风速客观订正方法。集合预报众数正确率及稳定性高于中值及平均值,因此基于集合预报众数,综合考虑历史数据的预报概率及集合预报各个成员的分布情况进行客观订正,可以提高订正效果。订正后的6~7级、8~9级风速偏小的误差及TS评分有明显改进,其中72~120 h预报时效的8~9级风速预报的TS评分由0.04增加到0.44,能够有效提高中长期时效大量级风速的预报能力。订正的风速产品对于我国近海冷空气及台风大风天气过程有较好的预报效果。  相似文献