近50年来(1960—2007年)长江流域20 cm口径蒸发皿蒸发量与太阳辐射变化的对比

利用长江流域147个气象站点1960—2007年的地面观测数据,通过计算,对比分析了长江流域20 cm口径蒸发皿蒸发量与太阳辐射的变化关系.结果表明:长江流域近50年来蒸发皿蒸发量变化和太阳辐射变化呈显著正相关关系,二者均呈现显著下降趋势,蒸发皿蒸发量随太阳辐射的变化产生相应波动变化,而且中下游地区蒸发皿蒸发量变化受太阳辐射变化的影响程度更为明显;就季节变化而言,春夏秋冬4个季节长江流域蒸发皿蒸发量变化和太阳辐射变化同样呈现明显下降趋势,春、夏、秋3个季节二者变化关系高度相关,这三季对于流域全年蒸发皿蒸发量减少的贡献也最大;长江流域太阳辐射的显著下降是导致20 cm口径蒸发皿蒸发量持续降低的主要原因之一.     

中国近30年太阳辐射状况研究

该文统计了中国地区1961～1990年近30年地面总辐射、直接辐射和散射辐射的变化。结果表明,中国大部地区近年来太阳总辐射和直接辐射呈减少趋势。在排除了大部分云的影响后,对太阳辐射的统计也给出了类似结果。对云量和地面能见度近30年变化规律的统计分析发现,中国大部分地区的能见度呈下降趋势,但云量的变化并不明显。初步认为,近年来大气混浊度和大气中悬浮粒子浓度的增加是引起中国某些地区直接辐射量下降的可能原因之一。     

Decreasing trend of sunshine hours and related driving forces in Southwestern China

Total hours of sunshine are one of the most important factors affecting climate and environment, and its long-term variation is of much concern in climate studies. Trends of temporal and spatial patterns in sunshine hours and related climatic factors over southwestern China are evaluated for the period 1961–2009 based on data from 111 standard meteorological stations. The results showed that southwestern China is experiencing a statistical decrease of sunshine hours, at the rate of 31.9 h/10a during 1961–2009. The decline was particularly strong in summer, whereas it is nonsignificant in winter. Spatially, statistically significant decreases of sunshine hours mainly occurred in lower altitude regions, especially in the Sichuan basin and Guizhou plateau. Sunshine hours have a high correlation with wind speed, relative humidity, precipitation, cloud cover, surface downwards solar radiation flux, and cloud water content, with wind speed showing the strongest relationship to sunshine hours, implicit in the close correlation (temporally and spatially) between the two variables. Changing water vapor and cloud cover influence sunshine hours in southwestern China. In addition, the increased surface downwards solar radiation flux also made some contribution to a rise of sunshine hours during 1991–2009. The larger decreasing trends of sunshine hours at urban stations than rural stations may reflect the effect of urbanization on sunshine hours. Variations are dominated by the comprehensive functions of multiple factors owing to the complex nature of effects on sunshine hours.     

山西省太阳能资源时空分布特征及利用潜力评估

按照中国气象局发布的太阳能资源评估方法,利用山西省近30 a 3个辐射观测站的太阳总辐射资料和105个站的日照资料,采用气候学方法计算了山西省的太阳总辐射,在分析山西省太阳总辐射的空间分布和时间演变特征的基础上,计算了山西省太阳能资源的各种参数,对区域太阳能资源潜力进行了客观评估。结果表明山西省太阳能资源储备丰富、稳定、可开发利用日数较多,特别是山西北部地区,尤其适合进行太阳能资源开发利用。     

四川省太阳能资源气候学计算

利用SMARTS模式计算晴天总辐射,充分考虑大气对太阳辐射的削弱作用和海拔高度的影响,以四川省为例,建立了复杂自然环境条件下基于日照百分率的太阳能资源气候学计算方程。该方法不仅物理意义明确,而且计算结果误差明显降低;与实测值相比,7个辐射站年地面太阳总辐射曝辐量的相对误差均低于7%;与初始值采用天文辐射曝辐量的方法相比,无论是相对误差值还是离散程度,均降低一半以上。该方法较好地解决了在一个地形复杂、气候多变的区域采用同一计算方程的难题,从而有效避免了过去采用分区方法带来的边界不连续问题,对我国东西高差大、干湿变化明显的特殊情况具有应用价值。     

锡林浩特市太阳辐射变化及相关气象要素分析

利用1990—2010年锡林浩特气象站太阳总辐射、日照时数、日照百分率、降水量、气温以及总云量的观测资料,运用5a滑动平均及最小二乘原理等方法,分析了锡林浩特市1990—2010年来的总辐射变化规律,并分析了气温、降水、日照、云量等的变化以及与太阳总辐射的相关关系。研究结果表明,锡林浩特市太阳总辐射呈现波动增加的趋势,但四季太阳辐射量在近21a的年际波动略有不同。相关要素分析表明,太阳总辐射与日照时数和夏季、秋季气温有很显著的正相关关系,与降水量和春季、夏季的总云量呈负相关关系。     

气候变化对中国华北地区办公建筑供热制冷能耗的影响评估

以中国华北地区五大城市办公建筑为例,利用1961—2017年气象数据和TRNSYS软件模拟的供热制冷负荷数据,评估了气候变化背景下华北地区建筑供热制冷负荷的变化。在此基础上,对模拟负荷和气象要素进行多元线性逐步回归分析,揭示了影响建筑供热、制冷负荷的主要气象因子。结果表明：1961—2017年中国华北五大城市供热负荷均呈下降趋势,降幅为0.05（石家庄）—0.13 kWh·m^-2·（10 a）^-1（呼和浩特）;各城市制冷负荷的变化不同,仅呼和浩特为增多,增幅为0.04 kWh·m^-2·（10 a）^-1,其余城市制冷负荷无明显变化;从总负荷来看,各城市均呈下降趋势,降幅为0.05（太原）—0.10 kWh·m^-2·（10 a）^-1（呼和浩特）。由供热制冷负荷与气象要素的回归分析可知,冬季供热负荷主要受气温影响,五大城市的显著增温导致供热负荷减少;与此不同,夏季制冷负荷主要受气温、太阳辐射的共同影响,呼和浩特平均气温和太阳辐射均呈显著上升趋势,导致其制冷负荷显著增加。其他城市气温显著升高,而太阳辐射显著降低,二者的综合作用导致制冷负荷没有明显的变化趋势。总体来看,在气候变暖背景下,中国华北地区冬季供热负荷明显降低,而夏季制冷负荷并未明显增加,导致总负荷显著降低,气候变暖总体上对建筑节能有利。     

2020年上半年“COVID-19”疫情期间气象条件变化对四川盆地城市污染物质量浓度影响初步分析

大气污染物质量浓度变化主要受气象条件和人为排放变化所控制。2020年上半年在“新冠”疫情影响背景条件下,四川盆地的六项主要污染物质量浓度较往年有不同程度的变化,为了区分这些变化受气象条件和人为排放变化各自的影响程度,开展了气象条件变化对四川盆地污染物质量浓度影响的初步分析。分析结果表明:2020年1～6月整体空气质量优于2019年同期。主要影响污染物浓度的气象参数中,成都平原、川东北地区平均风速与往年相当,川南地区平均风速低于往年。从2020年3月开始,盆地各个城市的总降水量明显偏少,其中5月降水偏少情况最为严重,对应的相对湿度在5月同比较低。平均温度2020年高于2019年,尤其是5、6月平均温度较往年偏高大约4～5°C。月日照总时长从3、4月开始明显长于往年。用固定污染源,改变初始气象条件的方法进行数值模拟结果表明,PM2.5和PM10相似,1、2月模拟结果低于2019年,3、4月高于往年,5、6月同比偏低,主要偏差区域在川南城市群。SO₂ 在1、2月气象条件有利于扩散,3月川东北不利扩散,其余月份差距不明显。NO₂在2月气象条件较为不利,CO不利的月份为4月。4月气象条件有利于臭氧扩散,而5、6月盆地气象条件对O₃污染过程起了较强的推动作用。定量分析各个城市污染物浓度贡献率表明,受疫情影响,除臭氧外的颗粒物和气体污染物在1~4月人为排放贡献为负,5、6月由于全面复工复产,导致盆地的污染物浓度也有所上升,人为排放贡献率也大幅增加。O₃由于人为排放增加与不利气象条件叠加,导致盆地O₃污染情况较为严重。     

Establishing a ultraviolet radiation observational network and enhancing the study on ultraviolet radiation

On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method for ultraviolet radiation (UV) in clear sky is obtained. The results show that the calculated values agree well with the observed, with maximum relative bias of 6.2% and mean relative bias for 24 months of 1.9%. Good results are also obtained when this method is applied in Guangzhou and Mohe districts. The long-term variation of UV radiation in clear sky over the Beijing area from 1979 to 1998 is calculated, and the UV variation trends and causes are discussed: direct and indirect UV energy absorption by increasing pollutants in the troposphere may have caused the UV decrease in clear sky in the last 20 years. With the enhancement of people‘s quality of life and awareness of health, it will be valuable and practical to provid UV forecasts for typical cities and rural areas. So, we should develop and enhance UV study in systematic monitoring, forecasting, and developing a good and feasible method for UV radiation reporting in China,especially for big cities.     

渠江流域汛期强降水时空分布特征

本文从分析研究渠江流域汛期强降水时空分布入手,试图揭示该流域21世纪以来洪水频发的原因。经对渠江流域1970~2012年降水资料分析研究得出:(1)渠江流域汛期降水量、暴雨日数、降水变差系数呈“北大南小”的空间分布;“北区(河流汇水区,下同)”近年来汛期降水量增大、暴雨频率增加、降水趋于极端;(2)短时强降水多发生在04~08时,频发区主要位于“北区”,近年来频次呈上升趋势;(3)小时雨强极值“北区”普遍大于“南区”;近43年渠江流域汛期小时雨强极值总体呈增大趋势,“北区”尤为明显。因此,渠江流域汛期发生的强降水趋势性变化,是导致该流域洪水频发的主要原因之一。      

Study of Distinctive Regional Features of Surface Solar Radiation in North and East China

Solar radiation is an important energy source for plants on the earth and also a major component of the global energy balance.Variations in solar radiation incident at the earth's surface profoundly affect the human and terrestrial environment,including the climate change.To provide useful information for predicting the future climate change in China,distinctive regional features in spatial and temporal variations of the surface solar radiation (SSR) and corresponding attributions (such as cloud and aerosol) are analyzed based on SSR observations and other meteorological measurements in North and East China from 1961 to 2007.Multiple models,such as the plane-parallel radiative transfer model,empirical and statistical models,and corrclation and regrcssion analysis methods are used in the study.The results are given as follows.(1) During 1961-2007,the total SSR in North China went through a process from quickly “dimming” to slowly “dimming”,while in East China,a significant transition from “dimming” to “brightening” occurred.Although there are some differences between thc two regional variation trends,long-term variations in SSR in the two regions are basically consistent with the observation worldwide.(2) Between the 1960s and 1980s,in both North and East China,aerosols played a critical rolc in the radiation dimming.However,after 1989,different variation trends of SSR occurred in North and East China,indicating that aerosols were not the dominant factor.(3) Cloud cover contributed less to the variation of SSR in North China,but was thc major attribution in East China and played a promoting role in the reversal of SSR from dimming to brightening,especially in the “remarkable brightening” period,with its contribution as high as 70％.     

Study of distinctive regional features of surface solar radiation in North and East China

Solar radiation is an important energy source for plants on the earth and also a major component of the global energy balance. Variations in solar radiation incident at the earth’s surface profoundly affect the human and terrestrial environment, including the climate change. To provide useful information for predicting the future climate change in China, distinctive regional features in spatial and temporal variations of the surface solar radiation (SSR) and corresponding attributions (such as cloud and aer...     

邯郸太阳辐射时空分布特征

利用邯郸1980—2017年气象观测资料和河北乐亭太阳辐射观测资料,基于Hybrid radiation模型,估算邯郸近38 a太阳辐射,采用线性倾向率、突变检验、复小波分解等方法,分析邯郸太阳辐射的空间特征、线性趋势、突变和周期。结果表明:邯郸年辐射值为5 000～5 300 MJ/m2,春、夏季太阳辐射约是秋、冬季的2倍,大部分县太阳辐射资源很丰富。邯郸太阳辐射总体呈下降趋势,期间经历了连续减少、稳定维持和缓慢增长3个阶段,近10 a太阳辐射的缓慢增长主要是由春、夏季太阳辐射增加引起的。邯郸春季没有突变点,夏、秋、冬季和年序列的突变点分别为1995、1999、2001和1996年,突变年之后,下降趋势减缓。除春季外,邯郸太阳辐射存在2～4 a显著的短震荡周期。     

THE VARIATION FEATURES OF AGROCLIMATIC RESOURCES AND CROP YIELD OF CHINA IN RECENT 40 YEARS

ＴＨＥＶＡＲＩＡＴＩＯＮＦＥＡＴＵＲＥＳＯＦＡＧＲＯＣＬＩＭＡＴＩＣＲＥＳＯＵＲＣＥＳＡＮＤＣＲＯＰＹＩＥＬＤＯＦＣＨＩＮＡＩＮＲＥＣＥＮＴ４０ＹＥＡＲＳＧａｏＳｕｈｕａ（高素华）ａｎｄＺｈａｎｇＹｕ（张宇）ＲｅｓｅａｒｃｈＣｅｎｔｅｒｆｏｒＡｇｒｉ...     

1981—2019年四川省霾日时空变化特征及成因分析

利用1981—2019年气象观测资料,分析了四川霾日的时空变化特征,并分析了污染物排放量和气象条件变化对霾日的影响。结果表明:(1)四川盆地为霾日高发区,年均霾日达53.7 d,其中轻、中、重度霾日数分别为26.9、24.1和2.7 d,川西高原年均霾日数不足1 d。霾日高值区主要分布在盆地的中部、东部及南部,轻、中、重度霾日高值区分布与霾日基本一致。(2)近39 a盆地霾日总体呈下降趋势,气候倾向率为-0.03 d/10 a,霾日数及霾分布范围在20世纪90年代达到最大,进入21世纪后霾日数和霾范围呈减小趋势。(3)霾在冬季发生频繁,冬季年均霾日数达24.7d,且盆地大部地区超过30 d。(4)近39 a盆地共发生持续性霾12 782次,自贡市、德阳市、内江市、乐山市为持续性霾的高发区;盆地共发生区域持续性霾509次,其中10 d的区域持续性霾发生的次数最多,占比为87.8%。(5)盆地霾天气的主要贡献污染物为PM2.5和PM10。二者排放量在20世纪90年代达到最大,进入21世纪后开始减少,21世纪10年代减少最为明显。21世纪10年代前盆地平均气温升高、相对湿度下降,污染物的排放与气象条件的共同作用,导致霾事件出现频率较高。随着城市生态文明的建设与治理,在21世纪10年代,盆地区域污染物排放减少,区域升温率减小,相对湿度显著升高,霾出现频率有所降低。     

Spatiotemporal variations of potential evapotranspiration and aridity index in relation to influencing factors over Southwest China during 1960–2013

This study investigated the spatial–temporal patterns and trends of potential evapotranspiration (ET₀) and aridity index (AI) over Southwest China during 1960–2013 based on daily temperature, precipitation, wind speed, sunshine duration, total solar radiation, and relative humidity data from 108 meteorological stations. The Penman–Monteith model, Mann–Kendall (M–K) test, moving t test, and Morlet wavelet method were used. The results indicated that ET₀ and AI across the region displayed decreasing trends, but the former was significant. After 2000, regionally average trends in ET₀ and AI increased rapidly, indicating that droughts increased over Southwest China in recent years. Spatially, the changes of ET₀ and AI were dissimilar and not clustered, either. Temporally, both ET₀ and AI displayed obvious abrupt change points over different timescales and that of AI was during the winter monsoon period. Significant periodic variations with periods of 27, 13, and 5 years were found in ET₀, but only of 13 and 5 years existed in AI. Correlation analysis revealed that the sunshine duration and wind speed were the dominant factors affecting ET₀ and that AI showed strong negative correlation with precipitation. The findings of this study enhance the understanding of the relationship between climate change and drought in Southwest China, while the mechanism controlling the variation in drought requires further study.     

A composite analysis of diurnal cycle of GPS precipitable water vapor in central Japan during Calm Summer Days

Summary The diurnal variations of water vapor in central Japan were investigated with GPS-derived precipitable water (PWV) and surface meteorological data as classified to three kinds of locations. Twenty-five clear days in central Japan in August 2000 were investigated to clarify the role of water vapor in the nocturnal maximum in the diurnal cycle of convective rainfall. The diurnal variations of PWV and some meteorological factors were composite during the selected days at 6 stations. The PWV shows a clear diurnal cycle with the amplitude of 3.4 mm to 8.8 mm and changes little during the period from the morning to noon. The daily amplitude of PWV is the largest in basin and smallest in plain although mean of PWV keeps high value in plain. A typical feature of the diurnal variation in central Japan is a maximum appearing in the evening. The time of maximum is from 1800 LST to 2000 LST, and minima appears at noon nearly in mountainous area and basin, while in early morning in plain. The diurnal maximum of PWV appears earlier in mountainous region than in plain. A diurnal cycle of specific humidity can be observed in all locations, and the amplitude in mountainous region is especially large compared with that in basin and plain. It is important to notice that there are remarkable differences in specific humidity among the six stations. The results suggest that the diurnal variation of PWV seems to be strongly affected by the local thermal circulations generated by the topography around these stations. The moisture transport causes the differences in phase of the diurnal cycle of PWV between different locations as well as the phase difference in precipitation. A very clear diurnal variation in surface air temperature is similar to that of solar radiation, with a minimum in the morning and a maximum in early afternoon. Maximum of surface wind speed are corresponded to peak of precipitation very well. It can be concluded that the amplitude of solar radiation increases with altitude as opposed to the situation of PWV generally. The precipitation observed frequently in the evening also shows a similar diurnal variation to that of the PWV, indicating the peak of precipitation appearing in late afternoon or in the evening over central Japan. Meanwhile the PWV reaches its nocturnal maximum. There is a good relationship between the diurnal cycle of observed precipitation and that of the PWV. Authors’ addressess: Guoping Li, Department of Atmospheric Sciences, Chengdu University of Information Technology, #3 Section 3, Ren Min Nan Road, Chengdu, Sichuan 610041, P.R. China; Dingfa Huang, Department of Surveying Engineering, Southwest Jiaotong University, Chengdu, China; Fujio Kimura, Tomonori Sato, Institute of Geoscience, University of Tsukuba, Tsukuba, Japan.     

四川省降水相态识别判据研究

本文运用1981~2013年四川省156个国家级地面观测站的原始气象记录整编数据,分析了四川省雨、雨夹雪和雪三种降水相态的气候分布特征,并从地面要素和高空要素两个方面详细分析了不同降水相态对应的变量阈值,主要结论如下:(1)降雨日数的第一特征向量近些年呈现出减少趋势,第二特征向量在雅安和广元地区的降水日数有所增加,攀西地区降水日数在减少;从降雪日数的第一特征向量看,四川地区降雪日数近些年也呈现减少趋势,第二特征向量四川中部一线近些年的降雪日数有所增加;雨夹雪日数第一特征向量说明四川大部分地区雨夹雪日数近20年都在减少,阿坝州地区的雨夹雪日数在增加,第二特征向量的趋势并不明显,第三特征向量近15年盆地地区的雨夹雪日数有所增加,川西高原和攀西地区的雨夹雪日数在减少。(2)地面和高空近地层的温度(T)和露点温度(Td)对区分降水相态有较好的指示意义。盆地西部,T_850hPa对三种降水相态有较好区分;盆地南部,各要素都能很好的区分雨和雪两种降水相态,但是雨夹雪与雪并不好区分;盆地东北部,只有H_{700-第一层}较容易区分三种不同的降水相态。川西高原上,H_{500-第一层}为区分三种不同降水相态的最佳高空要素;攀西地区,T_第一层、T_600hPa、零度层高度3个要素是识别三种不同降水相态的较好指标。      

西南地区夏季降水预测模型

从业务预报角度，对影响西南地区夏季降水的主要物理因子，如高原因子、西风带系统、副热带高压等因素进行了分析，在此基础上建立了具有一定物理基础的夏季降水预测模型，在近年来汛期降水预测中取得了明显效果。     

华南地面太阳辐射状况及其转折特征分析

利用华南地区1961—2003年的太阳总辐射、直接辐射和散射辐射资料分析了该地区地面太阳辐射状况,包括年际变化和季节变化,重点分析了该地区太阳总辐射在1980—1990年代期间的转折过程,并与全国平均状况进行对比。结果表明：1961—2003年,华南地区的总辐射和直接辐射整体呈下降趋势,散射辐射的变化不显著,与全国平均辐射状况的变化趋势一致。1983年之前,华南总辐射处于迅速下降阶段,之后发生转折开始回升,至2001年前后已经恢复到平均水平。华南地区总辐射和散射辐射的季节变化非常明显,夏季最高,春秋两季次之,冬季最低,一年中散射辐射的最高和最低值相比总辐射提前一个月出现。另外,结合云量和能见度资料初步分析了广州市地面太阳辐射的变化和转折过程,表明广州地面太阳总辐射的下降及转折过程主要与该地区的大气清洁程度相关。