基于信息扩散理论的长江中下游地区高温热害风险分析

基于长江中下游地区85个站点1961—2008年水稻减产率,采用基于信息扩散理论的信息分配方法,研究长江中下游地区水稻高温热害风险的年代际变化和空间分布。结果表明,20世纪60年代风险值相对较小,高温热害发生较少,2000年以后风险值较大,灾情较重,高温热害风险的变化呈增加的趋势。发生高温热害风险较大的地区主要位于研究区的安徽、浙江、湖北西部和东部以及江西东北部和中部地区。其中,浙江丽水和湖北宜昌地区风险值都超过了0．25;江苏东南部、湖南西南和东北部地区属于高温热害风险较低的地区。     

粤北地区高温热害气候特征及其对早稻产量的影响

利用连州1953 ～2010年58年地面观测站气象资料、农业气象观测站水稻观测资料,以日平均温度≥30℃且日最高温度≥35℃为指标,分析了粤北地区双季早稻抽穗扬花期和灌浆成熟期高温敏感发育期里高温热害气候特征及其对早稻产量的影响.结果表明:粤北地区58年里共出现高温热害42次;进入21世纪以来,高温热害的出现次数、严重...     

近50年气候变暖对黑龙江省玉米增产贡献的研究

使用黑龙江省1961—2008年22个站的逐日气象资料和玉米主产县的产量资料,确立基准时段,建立气温影响系数,分析气候变暖对黑龙江省玉米单产增加/减少的贡献率。结果表明:近50年来,气候变暖总体上对黑龙江省玉米单产增加趋势有利。以1961—1969年为基准时段,相对于20世纪60年代,70年代、80年代、90年代和21世纪初气候变暖的贡献率分别为16.8%、16.0%、20.9%和23.9%;以1970—1983年为基准时段,相对于20世纪70年代,80年代、90年代和21世纪初气候变暖的贡献率分别为3.6%、9.2%和11.2%。     

基于灾害风险理论的湖北水稻高温热害风险分析及区划

高温热害是长江流域最主要的气象灾害之一,科学评估热害风险是防灾减灾的基础。本文利用近60年气象观测资料,对湖北高温热害的时空分布特征进行了分析;基于自然灾害风险基本理论,建立了包括影响水稻结实率关键期的热害强度、灾害发生时承灾体实际暴露度、灾害脆弱性等因素的高温热害风险评价模型,并进行了风险分析与区划。结果表明：高温天气出现概率高的时段是7月下旬,其中7月第6候为最高。从高温热害风险指数上来看,7月第3候抽穗开花水稻的热害风险最高,此后随时间的推移,热害风险降低;湖北现行的一季中稻抽穗开花期处于风险较高的时段,推迟5天其热害风险指数可下降20%左右;推迟15天以上热害风险指数将降低50%以上。江汉平原稻区是湖北高温热害风险低发地区,鄂东南及鄂西北地区是热害风险高发地区;针对各区热害特点提出了风险应对措施。     

江苏水稻高温热害的发生规律与特征

用江苏1961—2007年47 a气象资料、农业气象观测站水稻观测资料,研究分析了江苏单季稻拔节期和孕穗扬花期2个高温敏感期,高温热害发生空间分布、时间变化。结果表明:常发生高温热害的地区主要分布在淮河以南地区,尤以宁镇扬丘陵地区为重,该地区47 a发生高温热害的总次数达到40次以上;而且年代际上表现为2001—2007年最重,1960 s次之,1980s最少。     

江西早稻高温热害发生时间分布特征

以江西早稻为例,利用1981—2016年气象资料、早稻高温热害灾情史料和生育期资料,构建历史早稻高温热害样本集合,在Kolmogorov-Smirnov（K-S）分布拟合检验的基础上,采用信息扩散方法计算得到早稻高温热害总样本和不同持续日数（3~5 d,6~8 d和8 d以上）不同等级（轻度、中度、重度）热害在早稻抽穗期前后的发生概率。结果表明:早稻高温热害起始于抽穗前6 d至抽穗后20 d,抽穗扬花期发生概率最高,随着早稻进入乳熟期高温热害发生概率逐渐降低。早稻抽穗扬花期持续3~5 d早稻高温热害以轻度、中度为主,5 d以上中度、重度高温热害发生概率为98.77%;随着早稻进入乳熟期,高温热害以中度和轻度为主,重度高温热害概率显著降低。早稻轻度高温热害的主要致灾时段为抽穗至灌浆中期,中度高温热害的主要致灾时段为抽穗至灌浆中前期,而重度高温热害的主要致灾时段为孕穗期至灌浆初期。     

江南雨季降水季节内演变及其年际、年代际变化特征

利用1961—2008年逐日降水资料,在对比我国东南部各地区气候态降水特征的基础上,着重探讨了江南地区(110~120°E、24~30°N)雨季降水的季节内变化特征及其年际、年代际变化规律。结果表明:1)江南雨季气候态降水的季节内变化具有明显的双峰型特征,两个峰值集中期分别是4、6月中旬前后。4月中下旬第一个降水峰值率先出现在江南地区,之后峰值降水南移,于6月上中旬华南地区达峰值集中期,之后强降水才逐渐北移,6月中下旬又回至江南地区,使江南地区降水达第二个峰值集中期。2)我国江南地区区域平均的双峰降水与4—6月的实际降水之间的相关系数达0.69,这表明双峰型降水确实反映了江南雨季降水的季节内演变特征。3)江南雨季降水双峰型的季节内变化特征具有明显的年际、年代际变化周期。年际变化周期为2~3 a,强信号主要集中在20世纪60年代后期到70年代中期以及80年代中期到21世纪初;年代际变化周期约为8~10 a,在整个时间域上都存在,最强信号集中在80年代初到90年代末期。4)年代际尺度上,江南雨季降水的季节内变化特征(双峰型态)具有隔代显著的特征,即20世纪60、80年代及21世纪初双峰型特征显著,而20世纪70、90年代双峰型特征不显著。     

中国干旱发生频率的年代际变化特征及趋势分析

利用1951年1月—2007年10月中国160站逐月降水资料计算了12个月时间尺度的标准化降水指数（ISP）。依据旱涝等级划分标准统计中国各年代干旱发生的频率,并用Mann-Kendall法分析干旱的年代际变化趋势。结果表明,20世纪50年代中国干旱集中发生在新疆南部,60年代主要发生在新疆北端至黄河上游一带地区和以长江中下游为中心的东南部地区,70年代发生在黑龙江、吉林一带以及长江中游地区,80年代发生在西南、华北的两条纬向分布带上,90年代发生在长江、黄河中游地区,21世纪初干旱主要集中在华北北部和内蒙古东部地区。和此前10a相比,趋向干旱的地区在20世纪50—60年代主要位于新疆北部、内蒙古东部以及长江下游至东南部地区,60—70年代主要位于东北地区,70—80年代主要位于山东、西南东部,80—90年代主要位于长江、黄河中游之间,90年代至今主要位于华北北部、内蒙古东部和黑龙江东部地区。80年代前后中国干旱高发区的地理分布发生了一次年代际跃变。50—70年代中国干旱主要发生在西北、东北、江淮流域以及长江中下游至华南地区,而80年代至今干旱高发区转移到以前的干旱低发区。50年代至今,吉林和黑龙江东部以及自河北至贵州的狭长干旱带的干旱化趋势增长迅速,而新疆、甘肃、青海一带的干旱化趋势显著下降。     

气候因素对2000年小麦生长发育的影响浅析

翼城县位于临汾地区东南部。小麦种植面积2.3万hm2,其中旱地1.5万hm2。1999～2000年度受拉尼娜等气候因素影响,小麦生育期间降水少,分布不均;气温高,冷热交替明显;风日多,浮尘、沙尘暴天气频繁;湿度低,干热风危害严重,致使全县小麦大幅度减产,其中2千hm2晚播麦田基本绝收,预计总产62500吨,较上年的81860吨减产23.7％,较历史最高年(1990年)的100157吨减产38.0％,是近年来产量最低、减产幅度最大的一年。1气候概况及特点　　小麦生育期间,降水、温度、日照等气候因素变化异常,降水量150.7mm,比历年偏少2～3成。有效积温达21…     

四川省2006年盛夏罕见高温干旱分析

2006年盛夏,四川省盆地区发生严重的高温干旱,本文利用实时和历史资料对该区域、该时段的气候特点作了综合分析.盛夏异常高温出现时间早,高温日数持续时间长,高温天气影响范围广.8月中旬为全盆地高温最严重时段,广安市出现全省高温中心.9月1日,华蓥山市的日最高气温再创新高,达43.6℃,为全省最高值.盛夏盆地降水为1961年以来历史最小值,旱区连续无降雨日数显著偏多,南充、广安、遂宁是省高温干旱最严重地区.通过对四川盆地16个测站46年(1961年～2006年)7～8月平均气温资料和46年7～8月盆地100多站平均降水量资料进行Mann-Kenall统计方法分析,盆地7～8气温,20世纪70年代属于高温阶段,20世纪80年代开始下降属于低温阶段,90年代中后期开始上升,但上升幅度慢于盆地秋季和冬季气温,2006年夏季处于上升期内.对盆地7月平均降水量进行分析判断,20世纪70年代后期到20世纪90年代初期属于峰值区;20世纪90年代中后期开始缓慢下降,2006年处于低谷区.     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

IMPACT OF ATMOSPHERIC LOW-FREQUENCY OSCILLATION ON THE IMMIGRATION OF NILAPARVATA LUGENS(STL) IN HUNAN AND JIANGXI PROVINCES

Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration.     

A COMPARATIVE ANALYSIS OF ATMOSPHERIC AND OCEANIC CONDITIONS BEFORE THE OCCURRENCE OF TWO TYPES OF EL NIO EVENTS

The atmospheric and oceanic conditions before the onset of EP El Ni?o and CP El Ni?o in nearly 30 years are compared and analyzed by using 850 hPa wind, 20℃ isotherm depth, sea surface temperature and the Wheeler and Hendon index. The results are as follows: In the western equatorial Pacific, the occurrence of the anomalously strong westerly winds of the EP El Ni?o is earlier than that of the CP El Ni?o. Its intensity is far stronger than that of the CP El Ni?o. Two months before the El Ni?o, the anomaly westerly winds of the EP El Ni?o have extended to the eastern Pacific region, while the westerly wind anomaly of the CP El Ni?o can only extend to the west of the dateline three months before the El Ni?o and later stay there. Unlike the EP El Ni?o, the CP El Ni?o is always associated with easterly wind anomaly in the eastern equatorial Pacific before its onset. The thermocline depth anomaly of the EP El Ni?o can significantly move eastward and deepen. In addition, we also find that the evolution of thermocline is ahead of the development of the sea surface temperature for the EP El Ni?o. The strong MJO activity of the EP El Ni?o in the western and central Pacific is earlier than that of the CP El Ni?o. Measured by the standard deviation of the zonal wind square, the intensity of MJO activity of the EP El Ni?o is significantly greater than that of the CP El Ni?o before the onset of El Ni?o.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on