河南省飞机人工影响天气空地数据传输系统的建设及应用

利用1970 -2009年三门峡40 a逐日雷暴观测资料, 采用线性倾向估计、Mann-Kendall法,小波分析,对三门峡市雷暴变化特征及突变情况进行了分析。结果表明:三门峡市年平均雷暴日数达16.5 天,高发季节为每年6—8月,高发时段为14-21时;年雷暴日数年代际线性变化呈下降趋势,气候倾向率为0.5个/10a。Mann-Kendall法检验显示,雷暴总体上呈减少趋势,没有发生突变。从小波分析的结果看, 三门峡市雷暴日序列具有3、6 a的短周期和8、14 a的长周期振荡变化,其中以6 a和8 a振荡周期为主要特征。     

1951-2010年大连市雷暴气候统计特征

利用1951-2010年大连雷暴资料,通过数理统计、Mann-Kendall和Morlet小波分析等方法研究大连市雷暴的气候特征。结果表明：近60 a年大连市年平均雷暴日较多,年际和年代际变化较大,年雷暴日呈增加趋势,每10 a雷暴日增加0.5 d。初雷日明显提前,终雷日明显推迟。雷暴有很强的季节性特点,集中出现在5-9月,而6-8月占近6成;夏季多于秋季,冬季最少。逐月平均雷暴分布与月平均气温、月降水量呈同相单峰形,7月雷暴出现高峰值,10月雷暴锐减。雷暴出现频率以02-06时为最高,16-20时为最低。雷暴日数的年际和年代际变化存在不显著的2-4 a和14-16 a振荡周期,并且在1972年发生突变。     

宜昌市雷暴气候特征分析

利用宜昌市9个气象观测站1965-2009年逐日雷暴资料,采用统计分析、线性趋势分析和Mann-Kendall法等方法对宜昌市雷暴的时空分布特征及变化规律进行了分析,结果表明:宜昌市雷暴日数分布特点是西南山区、丘陵多,东部平原少,年平均雷暴日数在29～43 d;近45 a宜昌市雷暴日数呈明显下降趋势,其中远安、五峰和宜都下降趋势最为显著;雷暴日数具有明显的季节变化,4-9月为雷暴天气多发期,月平均雷暴日呈单峰型,7月达到最高值9.6d;突变检验显示雷暴日数在1984年前后发生了气候突变;平均初雷日有推迟的趋势,平均终雷日有提前的趋势,雷暴活动期呈缩短趋势.     

电白雷暴气候特征及演变分析

利用线性回归、突变分析、小波分析等方法分析电白雷暴气候特征。结果表明:近53年来,电白雷暴主要集中在4至9月,其中8月最多,5月和7月的年雷暴日数变化较大;雷暴日数总体呈明显下降趋势,下降速率为6.4d/10a;结合M-K突变和滑动t突变检验,没有确定出雷暴日数的突变年份;雷暴日数存在准4年、8-9年、24年的震荡周期;雷暴日数的气候特征受大环流形势影响较明显,而受当地其它气象要素变化的影响较小。     

1961—2009年伊犁雷暴气候特征分析

根据伊犁10个气象站1961-2009年实测雷暴资料,运用EOF和小波分析等 方法,研究了伊犁雷暴的时空分布及变化特征,得出以下结论：(1)伊犁地区年均雷暴日数 为35．6 d,属中雷区,近49 a雷暴日数呈显著减少的趋势;(2)伊犁雷暴日数有着明显的垂 直地带性和纬度地带性,空间分布表现为南部多于北部,山区多于谷地,高值中心位于乌孙尔山脉南侧的昭苏一带,雷暴发生频率高的地区雷暴持续时间也较长;(3)5—8月为雷暴主要 发生期,占雷暴总日数的89．8％,其中6、7月雷暴出现频率最高,分别占雷暴总日数的 3O．O％、28．3％;(4)伊犁雷暴日数时间序列有着5—6 a、9一l2 a、2 a左右的振荡周期;(5)近 49 a北半球副高强度增强、面积增大并北扩是伊犁雷暴日数显著减少的重要原因之一。     

廊坊市雷暴气候特征及区划研究

利用廊坊市9个气象站1964—2011年的雷暴日资料,通过数理统计、线性趋势拟合和小波分析,研究了廊坊市近48 a来雷暴的时空分布特征和周期性特征,并结合信息扩散法,进行了不同雷暴日数下的概率区划.结果表明:廊坊市雷暴日的年际变化幅度较大,年均雷暴日数总体呈下降趋势,约每10 a减少2 d;廊坊市雷暴月、季变化呈明显的单峰型,雷暴主要发生在4—10月,其中夏季(6—8月)占全年的74.5%;中北部的雷暴日数明显多于南部地区;10a及以上周期在绝大部分地区具有全域性,而短周期3~5 a大多表现在20世纪90年代之前;随着雷暴日数的增大,雷暴发生高概率区逐渐北移,当雷暴日数异常偏大(>40 d)时,中部的部分地区也处于雷暴发生高概率区.     

1973—2012年承德市雷暴气候特征分析

基于1973—2012年承德市9个地面气象观测站逐日雷暴观测资料,利用线性分析、突变分析、小波分析等统计方法,对承德市雷暴日数变化特征进行分析。结果表明:承德市雷暴日数呈现出由西向东递减的空间分布特征,大部分地区处于"中雷区",丰宁、滦平、承德市达到"多雷区"级别;全市年平均雷暴日数为39.5d,最多年为55.3d,而最少年为27.6d;1973—2012年承德市雷暴日数呈现显著减少趋势,平均10a减少2d左右,并于2006年发生突变;承德市雷暴发生存在明显季节差异,高发期主要集中在夏季,呈单峰型分布,7月雷暴日出现最多;初雷日一般出现在4月上旬,近40a呈显著推迟趋势,终雷日一般出现在10月中旬;雷暴日数存在明显的年际变化,且呈现出4~6a周期振荡。     

百色市雷暴气候特征分析

利用广西百色市12个气象观测站1965—2009年的雷暴观测资料,采用气候倾向率、小波分析和保证率等方法,分析了近45 a雷暴的时空分布规律、气候变化趋势、周期性特征和不同保证率下初终期分布。结果表明:①百色市各地年平均雷暴日数在62 d以上,属于雷暴多发区;雷暴空间分布趋势为自西北部向东南部递减。②雷暴日的年际变化呈减少趋势,平均每10 a雷暴日数减少6 d左右。③雷暴日月分布具有单峰型特点,4—9月占全年雷暴日数的88.9%。④80%保证率下雷暴初日出现在3月上旬至3月下旬,80%保证率下雷暴终日出现在11月中旬至12月中旬。⑤小波分析结果表明,百色雷暴的年际变化普遍存在着3～4 a短周期和准8～12 a的长周期,由此推测未来几年百色可能处于少雷期。     

1961-2008年广东省雷暴时空变化与气候变暖的关系

为研究广东省雷暴时空变化与气候变暖的关系,通过对广东省内所有站点的观测数据进行均一性检验后,选取37个测站1961-2008年的雷暴和气温资料,采用趋势分析、Mann-Kendall突变检验、小波分析等方法,分析了广东省的雷暴日数和年平均气温的变化特征.结果表明,随着广东省各地年平均气温的升高,广东省年平均雷暴日数以每10年4.52 d速率减少,并且年平均雷暴日数与年平均气温分别存在准5、12、20年和4、8、12、20年的多时间尺度的演变特征.     

玉屏县50a雷暴气候特征分析

根据玉屏国家一般气象站1961年1月—2010年12月雷暴观测记录资料,采用最小二乘法对年雷暴日数进行线性模拟,结合5 a滑动平均和累计距平方法,分析玉屏县50 a来年雷暴日数的年、月、日变化特征。得出了如下结论:玉屏县近50 a来年雷暴日数总体上呈减少趋势,历年平均雷暴日数47 d,每10 a平均减少2 d;1985年为年雷暴日数出现转折的年份,但突变分析不显著。雷暴天气在全年均有发生,呈双峰型分布,最大峰值出现在7-8月,平均8.5 d和8.6 d,次大峰值出现在4月,平均7.6 d;夏季是雷暴天气多发季节,雷暴日数占全年的47%,春季是雷暴天气次多发季节,占雷暴日数38%,秋、冬季雷暴天气占8%和7%。一日中雷暴出现的高峰时段12-18 h,以14-16 h出现概率为最大,占26%。雷暴初日有提早趋势,终日有推迟趋势。     

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