Variation Characteristics and Tendency of Precipitation in Chaoyang Area between 1908 and 2008

According to the precipitation sequence of Beijing City from 1900 to 1958,the precipitation sequence of Chengde City were revised and extended.Then the precipitation sequence of Chaoyang City were revised and extended with the precipitation sequence of Chengde City to form 100-years precipitation sequence of Chaoyang.The results showed that the 100-years precipitation sequence of Chaoyang indicated a decreasing trend and obvious periodic variation with the change of age.That is,a 10-year rainy period (approximately 525.0 mm) appeared every 30 a,while the 30-year drought period was approximately 460.0 mm,65.0 mm lower than the former.Moreover,an obviously heavy drought lasting for 2-4 a appeared every 20 a.

The pattern characteristics of the tendency variations of earth resistivity and its relation to earthquakes

Through systematically summarizing the observational data of earth resistivity during 26 years from nearly a hundred stations in China, the author found that the pattern of the earth resistivity (ρs) tendency variations,based on monthly average data, could be divided into five types, three types of which were defined as anomalous variation, which have different qualitative and quantitative characteristics and different relations with earthquakes as well.The first type of tendency variation called “funnel” is related to strong earthquakes, the Second type called “scoop” has good corresponding relation with moderate earthquakes, and the third type called “tilt” has no relation with earthquakes. Preliminary discussions about the relations between the three types of ρs tendency variation patterns and earthquakes are made in this paper, according to the experimental results of pressed rocks. It is concluded that the different patterns of ρs tendency variation actually reflect the different stress conditions of underground soil-rock layers: the “funnel” type reflects high stress status, the “scoop” type shows moderate stress condition and the “tilt” type is related to stress relief. All of such knowledges mentioned above are very useful in making accurate medium-term earthquake prediction.

Long-term variation of storm surge-associated waves in the Bohai Sea

When investigating the long-term variation of wave characteristics as associated with storm surges in the Bohai Sea,the Simulating Waves Nearshore(SWAN)model and Advanced CIRCulation(ADCIRC)model were coupled to simulate 32 storm surges between 1985 and 2014.This simulation was validated by reproducing three actual wave processes,showing that the simulated significant wave height(SWH)and mean wave period agreed well with the actual measurements.In addition,the long-term variations in SWH,pattems in SWH extremes along the Bohai Sea coast,the 100-year retum period SWH extreme distribution,and waves conditional probability distribution were calculated and analyzed.We find that the trend of SWH extremes in most of the coastal stations was negative,among which the largest trend was-0.03 m/a in the western part of Liaodong Bay.From the 100-year return period of the SWH distribution calculated in the Gumbel method,we find that the SWH extremes associated with storm surges decreased gradually from the center of the Bohai Sea to the coast.In addition,the joint probability of wave and surge for the entire Bohai Sea in 100-year return period was determined by the Gumbel logistic method.We therefore,assuming a minimum surge of one meter across the entire Bohai Sea,obtained the spatial SWH distribution.The conclusions of this study are significant for offshore and coastal engineering design.

LONG-TERM VARIATIONS OF FOG AND MIST IN China's Mainland DURING 1951-2005

Fog is an important indicator of weather. Long-term variations of fog and mist were studied byanalyzing the meteorological data from 743 surface weather stations in China's Mainland during 1951-2005.In climatology, there are more foggy days in the southeast than in the northwest China and more in thewinter half of the year than in the summer half. The decadal change of foggy days shows regional variation.Southwest China is the region with the most foggy days, and more than 20 foggy days occur in SichuanBasin in one year. Persistent heavy fog usually appears in winter and spring over the North China Plain andNortheast China Plain. Misty days are much more frequent in the provinces south of the Yangtze River thanin the regions north of it, and there is an obvious increase of misty days after the 1980s. Southwest China isthe area with the most number of misty days, and more than 100 misty days occur in Sichuan Basin in ayear.

Dew amount and its long-term variation in the Kunes River Valley,Northwest China

Dew is an essential water resource for the survival and reproduction of organisms in arid and semi-arid regions.Yet estimating the dew amount and quantifying its long-term variation are challenging.In this study,we elucidate the dew amount and its long-term variation in the Kunes River Valley,Northwest China,based on the measured daily dew amount and reconstructed values(using meteorological data from 1980 to 2021),respectively.Four key results were found:(1)the daily mean dew amount was 0.05 mm during the observation period(4 July-12 August and 13 September-7 October of 2021).In 35 d of the observation period(i.e.,73%of the observation period),the daily dew amount exceeded the threshold(>0.03 mm/d)for microorganisms;(2)air temperature,relative humidity,and wind speed had significant impacts on the daily dew amount based on the relationships between the measured dew amount and meteorological variables;(3)for estimating the daily dew amount,random forest(RF)model outperformed multiple linear regression(MLR)model given its larger R^(2) and lower MAE and RMSE;and(4)the dew amount during June-October and in each month did not vary significantly from 1980 to the beginning of the 21^(st) century.It then significantly decreased for about a decade,after it increased slightly from 2013 to 2021.For the whole meteorological period of 1980-2021,the dew amount decreased significantly during June-October and in July and September,and there was no significant variation in June,August,and October.Variation in the dew amount in the Kunes River Valley was mainly driven by relative humidity.This study illustrates that RF model can be used to reconstruct long-term variation in the dew amount,which provides valuable information for us to better understand the dew amount and its relationship with climate change.

Research on Air Temperature Variation Characteristics and Trend in Tacheng Prefecture in Xinjiang during 1954-2008

[Objective] The aim was to analyze the changes characteristics of temperature in Tacheng.[Method] By dint of monthly average temperature from 1955 to 2008 in four typical meteorology station,Tacheng,Hebukesai’er,Tuoli and Wusu,the temperature multi-temporal scale characteristics and changes trend in future in Tacheng were expounded by small wave analysis and climate trend coefficient method.[Result] The average temperature in so many years in Tacheng was 5.88 ℃.The annual changes of temperature were relatively stable.The coefficient of changes were between 0.130-0.265.The extreme value was between 1.73-3.79;the sequence distribution of temperature showed plat peak form and the annual average temperature was divergence.The temperature in Tacheng had 5-year,9-year and 14-year period.It was in cold period in 1970 when average temperature was only 3.77 ℃.The 1980s was the warmest age in recent 54 years,reaching 8.10℃.In recent 90s,and comparing with 80s,temperature in Tacheng was decreasing,but still higher than that in 70s.It was forecasted that the temperature in future would increase.The annual average temperature in each area and the average temperature in each season in Tacheng increased significantly,with a range of 1.15-2.05 ℃/10 a.The smallest temperature increase speed in summer was 0.16-0.45 ℃/10 a.The annual average temperature changes speed was 0.40-0.78 ℃/10 a.[Conclusion] The temperature changes in Tacheng had positive corresponding trend toward the climate warming.

Characteristics and Trend Variation of Light,Temperature and Water Resources in Dongling District of Shenyang Province in Recent 49 Years

The meteorological data of light,temperature and water during 1961-2009 were selected to analyze the trend variation of climatic resources and provide the basis for developing and utilizing local climate resources.The results indicated that light resource presented the decreasing tendency in Dongling District,annual radiation reduced by 528 MJ/m2,and annual sunshine duration decreased by 333 h.The heat resource presented the increasing tendency,the average annual temperature increased by 1.04 ℃,and active accumulated temperature increased by 228 ℃.The general trend of annual precipitation declined slightly,precipitation resource during every age changed slightly and would tend to be stable.

THE RELATIONSHIP BETWEEN GLOBAL WARMING AND THE VARIATION IN TROPICAL CYCLONE FREQUENCY OVER THE WESTERN NORTH PACIFIC

The relationship between global warming and the variation in tropical cyclone (TC) genesis frequency is analyzed using the data of the Tropical Cyclone Year Book by the China Meteorological Administration and the National Centers for Environmental Prediction (NCEP) reanalysis data from 1949 to 2007. The observational results indicate that the average sea surface temperature (SST) in the Intertropical Convergence Zone (ITCZ) region (10°N– 20°N, 100°E– 140°E) increases by 0.6°C against the background of global warming, while the frequency of tropical cyclone geneses in this region decreases significantly. Generally, the rise of SSTs is favorable for the genesis of tropical cyclones, but it is now shown to be contrary to the normal effect. Most of the tropical cyclones in the western North Pacific (WNP) are generated in the ITCZ. This is quite different from the case in the Atlantic basin in which the tropical cyclones are mostly generated from the easterly wave. Our research results demonstrate that the ITCZ has a weakening trend in strength, and it has moved much more equatorward in the past 40 years; both are disadvantageous to the formation of tropical cyclones. Furthermore, our study also found that the ridge of the subtropical high tends to shift slightly equatorward, which is another adverse mechanism for the formation of tropical cyclones.

The seasonal variations in the significant wave height and sea surface wind speed of the China's seas

Long-term variations in a sea surface wind speed （WS） and a significant wave height （SWH） are associated with the global climate change, the prevention and mitigation of natural disasters, and an ocean resource exploitation, and other activities. The seasonal characteristics of the long-term trends in China＇s seas WS and SWH are determined based on 24 a （1988-2011） cross-calibrated, multi-platform （CCMP） wind data and 24 a hindcast wave data obtained with the WAVEWATCH-III （WW3） wave model forced by CCMP wind data. The results show the following. （1） For the past 24 a, the China＇s WS and SWH exhibit a significant increasing trend as a whole, of 3.38 cm/（s.a） in the WS, 1.3 cm/a in the SWH. （2） As a whole, the increasing trend of the China＇s seas WS and SWH is strongest in March-April-May （MAM） and December-January-February （DJF）, followed by June-July-August （JJA）, and smallest in September-October-November （SON）. （3） The areal extent of significant increases in the WS was largest in MAM, while the area decreased in JJA and DJF; the smallest area was apparent in SON. In contrast to the WS, almost all of China＇s seas exhibited a significant increase in SWH in MAM and DJF; the range was slightly smaller in JJA and SON. The WS and SWH in the Bohai Sea, the Yellow Sea, East China Sea, the Tsushima Strait, the Taiwan Strait, the northern South China Sea, the Beibu Gull and the Gulf of Thailand exhibited a significant increase in all seasons. （4） The variations in China＇s seas SWH and WS depended on the season. The areas with a strong increase usually appeared in DJF.

PECULIARITIES OF LONG TERM VARIATION OF SEA SURFACE TEMPERATURE IN TROPICAL WESTERN PACIFIC OCEAN

It is necessary to study the tropical western Pacific SST in association with variations of other parts of the globe. Two basic compositions are revealed of long-term variation in SST over three major tropical oceans since the 1950’s (linear warming and El Ni?o-La Ni?a oscillations) and typical patterns with which they are displayed over the oceans are compared. On the basis of it, difference in long-term variation of SST over western, central and eastern tropical Pacific is analyzed in details. It is pointed out that the El Ni?o-La Ni?a oscillations are relatively weak in the long-term variation of SST in the tropical western Pacific and linear warming trend there is replaced by interdecadal oscillations. Further understanding of the peculiarity over the region helps improve short-term climatic predictions in China.

Variations in the Summer Monsoon Rainbands Across Eastern China over the Past 300 Years

Based on reconstructions of precipitation events from the rain and snowfall archives of the Qing Dynasty （1736-1911）, the drought/flood index data mainly derived from Chinese local gazettes from 1736-2000, and the observational data gathered since 1951, the spatial patterns of monsoon rainbands are analyzed at different time scales. Findings indicate that monsoon rainfall in northern China and the middle-lower reaches of the Yangtze River have significant inter-annual （e.g., 5-7-yr and 2-4-yr） as well as inter-decadal （e.g., 20-30-yr and quasi-10-yr） fluctuation signals. The spatial patterns in these areas also show significant cycles, such as on a 60-80-yr time scale, a reversal phase predominates the entire period from 1736-2000; on a quasi-30-yr time scale, a consistent phase was prevalent from 1736 to 2000; and on a 20-yr time scale, the summer monsoon rains show different spatial patterns before and after 1870.

Variation Characteristics of Sunshine Hours and Its Reason Analysis over Loess Plateau of Shaanxi

[Objective] The research aimed to study variation characteristics of sunshine hours over Loess Plateau of Shaanxi during 1961-2010.[Method] By using the climate tendency rate,climate trend coefficient and linear correlation,the temporal and spatial variation characteristics of sunshine hours in Loess Plateau of Shaanxi in recent 50 years were analyzed.Moreover,the main reason for inducing variation of sunshine hours in the zone was discussed.[Result] In recent 50 years,the variation of annual sunshine hours in Loess Plateau of Shaanxi mainly presented decrease trend.The decrease zones were mainly located in windy desert region along the Great Wall line,central loess hilly region,most areas of plateau remains region and most areas of arid plateau region in north Weihe River.The increase zones were mainly located in west and northeast plateau remains region,southwest plateau remains region,some areas of arid plateau region in north Weihe River.Seen from four-season variation trend,except in spring,the sunshine hours in other seasons presented varying decrease trends.The decrease amplitude in summer was 24.34 h/10 a,and was the most significant.The second one was-16.62 h/10 a in winter.The decrease amplitude in winter was 3.55 h/10 a,and was unobvious.Seen from spatial variation,the annual sunshine hours presented significant increase trend in Mizhi of loess hilly region and significant decrease trend in Dingbian,Shenmu of windy desert region along the Great Wall line,Qingjian,Yanchuan of plateau remains region,Longxian,Fengxiang,Chunhua and Hancheng of arid plateau region in north Weihe River.There was no obvious variation trend in other research zones.The annual and four-season sunshine hours all presented negative correlations with rainfall,relative humidity,total cloud amount,low cloud amount,water vapor pressure and fog days.The sunshine hours presented positive correlation with visibility.The correlation coefficients between sunshine hours and relative humidity,rainfall,total cloud amount,water vapor pressure,fog days and visibility were all bigger in each region.[Conclusion] The research provided basis for analyzing climate variation over Loess Plateau of Shaanxi.

1990~2019年中国非风湿性瓣膜性心脏病疾病负担及变化趋势分析

目的:分析1990~2019年中国非风湿性瓣膜性心脏病(non-rheumatic valvuiar heart disease,NRVHD)疾病负担及变化趋势。方法:基于2019年全球疾病负担数据库收集1990~2019年中国NRVHD相关数据,分析这一时期NRVHD的粗发病率、粗患病率、粗伤残调整寿命年(DALY)及其年龄标化率等数据,并通过Joinpoint回归模型分析相应的变化趋势。利用灰色预测模型GM(1,1)预测2020~2029年中国NRVHD负担状况。结果:中国NRVHD粗发病率、粗患病率和粗DALY率从1990年的7.87/10万、123.21/10万和9.83/10万上升到2019年的22.85/10万、374.16/10万和11.95/10万;年龄标化发病率、年龄标化患病率从1990年的9.22/10万、169.04/10万上升到2019年的15.30/10万、262.85/10万,女性均高于男性;年龄标化DALY率从1990年的13.43/10万下降到2019年的9.07/10万,女性均高于男性。Joinpoint回归模型分析显示,年龄标化发病率、年龄标化患病率呈上升趋势,年龄标化DALY率呈下降趋势[平均年度变化百分比(AAPC)分别为1.86%、1.72%和-1.66%],变化趋势有统计学意义(P均<0.05)。1990~2019年不同年龄组人群的疾病负担整体呈上升趋势,其粗发病率、粗患病率及粗DALY率均随着年龄的增长而升高,60岁以上的老年人群是疾病负担的主要群体。灰色预测模型GM(1,1)结果显示,至2029年年龄标化发病率和年龄标化患病率分别增加到18.51/10万、303.26/10万,年龄标化DALY率下降到7.42/10万。结论:1990~2019年中国NRVHD的年龄标化发病率、年龄标化患病率呈上升趋势,年龄标化DALY率均呈下降趋势。NRVHD的疾病负担仍然较重,女性和高龄人群尤其需要关注。

基于聚类最小二乘法和斜率相结合的极值点延拓方法

针对经验模态分解法(empirical mode decomposition,EMD)对信号进行去噪处理中可能产生的端点效应问题,提出一种聚类最小二乘与斜率相结合的极值点延拓方法。该方法充分考虑了噪声对延拓方法的影响,利用聚类最小二乘法描述全局极值点的变化趋势,并结合信号的边界局部特征来确定延拓点的坐标信息。通过对仿真信号和陀螺仪实例信号展开研究,利用相似系数、均方根误差和正交性水平等指标对算法性能进行评价。实验结果表明:所提出的方法可以有效地抑制EMD端点效应,最大限度地避免了端点效应对中间数据的污染,从而提高了信号去噪的准确性和可靠性,为EMD在信号处理中的应用提供了一个可行且有效的解决方案。

西北四省太阳能资源分布与长期变化趋势分析

根据我国西北四省1978—2017年的观测数据,分析该区域太阳总曝辐量的空间分布特征,绘制太阳能资源区划图,并分析了以往研究中未涉及的太阳总曝辐量长期变化趋势。结果表明:西北四省多年平均年太阳总曝辐量为3 676~7 036 MJ/m^(2),且自西北向东南逐渐递减,高值区主要在青海大部、甘肃河西西部、宁夏大部与陕西北部。各季节太阳总曝辐量分布特征为夏季最高、春秋季次之、冬季最低。西北四省大部分地区太阳总曝辐量长期变化呈减少趋势,少部地区呈增加趋势,其中青海中西部区域减少最为明显,甘肃河西西部与武威地区、陕北部分地区增加趋势明显。在四季中,秋季太阳总曝辐量呈减少趋势的范围最大,春季太阳总曝辐量呈增加趋势的范围最大。研究结果对掌握西北四省太阳能资源的长期变化趋势与光伏电厂长期收益及风险防范有参考价值。

山西省1961—2022年典型区域降水变化特征分析

基于山西省典型区域(晋北地区、太原市和晋南地区)1961—2022年22个国家气象观测站的降水资料,应用气候倾向率、M-K(Mann-Kendall)趋势分析和突变检验方法,探究山西省典型区域的降水变化特征。结果表明:(1)近62年,山西省典型区域降水量符合山西省北少南多的纬向分布特征,且南部降水年际波动幅度较北部大。(2)三地降水分配情况均为夏季>秋季>春季>冬季,晋南地区夏季降水占比低于晋北地区和太原市,而春秋冬季降水占比高于两地。(3)降水年际变化趋势不同,晋北地区年降水呈增加趋势,太原市和晋南地区呈减少趋势。M-K突变分析表明,太原市和晋南地区年降水量在1965年发生了由多到少的突变,此外2020年左右太原市仍存在降水突变。(4)三地不同阶段变化趋势相同,1961—1981年为波动减少的多雨期,1982—2002年为波动减少的少雨期,1983—2022年为波动增加的多雨期。(5)四季降水变化趋势不同,晋北地区和太原市除夏季呈减少趋势外,春、秋、冬季呈现不同程度的增加趋势;晋南地区除冬季呈较显著增加趋势外,春、夏、秋季呈不同程度的减少趋势;各地四季降水均量存在不同程度的突变。

新疆农业碳排放时空特征及驱动因素研究

【目的】研究新疆农业碳排放的时空特征及驱动因素,为该地区推动农业农村绿色发展、实现“双碳”目标提供参考。【方法】以种植业、畜牧业、农业能源终端消费的19类碳源为原始数据,对2007—2021年新疆农业碳排放量和碳排放强度进行测算;以种植业和畜牧业的15类碳源为原始数据,对2010、2015、2020年新疆14个地州(市)碳排放量和碳排放强度进行测算;运用LMDI(对数平均除以指数法)模型对其驱动因素进行分析;运用灰色预测模型对新疆2022—2030年农业碳排放的发展进行趋势预测。【结果】2007—2021年新疆农业碳排放量总体呈现“平稳—上升—下降—上升”的趋势,农业碳排放强度总体呈现“下降—上升—下降”的趋势;2010、2015、2020年伊犁哈萨克自治州碳排放总量最高、克拉玛依碳排放总量最低、克孜勒苏柯尔克孜自治州碳排放强度最高,2010年巴音郭楞蒙古自治州碳排放强度最低,2015、2020年吐鲁番碳排放强度最低;农业碳排放驱动因素影响大小为:农业经济水平效应>农业结构效应>农业人口规模效应>农业生产效率;2022—2030年,预测新疆的农业碳排放量呈现增长趋势、强度呈现下降趋势。【结论】2007—2021年新疆农业碳排放总量整体呈现上升趋势,农业碳排放强度整体呈现下降趋势;农业经济水平效应对农业碳排放的增加有促进作用,农业结构效应、农业人口规模效应、农业生产效率对农业碳排放的增加有抑制作用;预计在2022—2030年,新疆农业碳排放量将逐年增加、农业碳排放强度将逐年下降,新疆农业减排固碳潜力巨大。

近60年江苏省气温变化特征

选取江苏省为研究区,对省内22个气象站的近60年气温逐月数据进行分析。通过数据统计、线性回归法对研究区内年均、四季气温进行时空变化特征分析。依托模糊综合评判模型对年均、四季气温及其变化幅度进行分类评定。结果表明:(1)江苏省多年平均的年及四季气温均呈现上升趋势,且各年代变幅不一,尤以20世纪60年代变幅(1.7℃)最大,除夏季外,其他三季上升趋势更为突出。(2)通过模糊综合评判模型计算,春冬两季气温等级属于一般级别,而夏秋两季属于较高级别;春季气温的变幅为一般级别,夏秋季的变幅为略小级别,冬季的变幅为略大级别。

Long-term variation and evaluation of air quality across Hong Kong region

Study of Air Quality Objectives(AQOs)and long-term changes of air pollution plays a decisive role in formulating and refining pollution control strategies.In this study,10-year variations of six major air pollutants were analyzed at seven monitoring sites in Hong Kong region.The continuous decrease of annual averaged concentrations of NO_(2),SO_(2),CO,PM_(2.5)and PM_(10)and numbers of days with severe pollution conditions validated the efficiency of the series of air pollution control schemes implemented by the Hong Kong region government.However,there is still a big gap to meet the ultimate targets described by the World Health Organization.Besides,the concentration of O_(3)at roadside and urban stations increased by 135%±25%and 37%±18%from 2011 to 2020,respectively,meanwhile the highest 8 hr averaged O_(3)concentration was observed as 294μg/m^(3)at background station in 2020,which pointed out the increasing ozone pollution in Hong Kong region.There was a great decrease in the annual times of air quality health index(AQHI)laying in“high”,“very high”and“serious”categories from 2011 to 2020 with the decrease rate of 89.70%,91.30%and 89.74%at roadside stations,and 79.03%,95.98%and 72.73%at urban stations,respectively.Nevertheless,the number of days categorized as“high”or above at roadside station was twice more than that in the urban station during the past ten years.Thus,more policies and attentions should be given to the roadside air quality and its adverse health effect to pedestrians on street.

平原河网地区生态水位计算分析

为了研究平原河网地区生态水位,以上海市青松片区域为例,采用滑动T检验和累积距平法,分析1952~2021年水位变化趋势,确定水位变异点;以水位变异点为界,分别采用保证率法和年内展布法计算变异前后及长序列时段区域内生态水位及年内过程,评估生态水位满足程度。计算结果表明:1997年为水位突变年份,突变后多年平均水位较突变前抬升0.22 m;以年内展布法计算的突变后生态水位与长系列相比,存在明显上涨,幅度在8.3%~15%之间,年内生态水位2.28~2.51 m,总体满足程度为98.3%。分析结果可为平原河网地区水生态环境保护、水资源调度决策提供参考。