商丘紫外线指数变化规律及气象因子影响分析

利用2003年4月至2006年6月商丘市气象台观测到的太阳紫外线指数资料及总云量、能见度、气温和相对湿度资料,分析了商丘市区紫外线指数的月、日变化规律以及气象因子与紫外线指数的关系。结果表明:①商丘紫外线指数1～2月和11～12月小,3～10月大,7～8月最大。②紫外线指数的日变化规律显著,基本上遵循正态分布,一天中辐射最强的时段在11:00～14:00,紫外线指数基本在6以上,辐射等级超过3级,紫外线照射强度中等以上。③紫外线指数与总云量、能见度、气温和相对湿度有较好的相关性。14:00的紫外线指数与同时次的总云量呈反相关,相关系数为-0.57;与能见度呈正相关,相关系数为0.64;与气温呈正相关,相关系数为0.46;与相对湿度呈反相关,相关系数为-0.8。     

商丘市紫外线辐射与气象因子的关系

利用2003年4月至2006年6月商丘太阳紫外线辐射强度资料及气象资料,分析了商丘市紫外线辐射的月、日变化规律及气象因子对紫外线辐射的影响.结果表明商丘紫外线辐射月际分布是,年初、年底辐射量小,3～9月辐射量大,最大辐射指数为11.4;紫外线辐射的日变化规律显著,基本上遵循正态分布,呈抛物线型变化,早晚辐射量小、中午前后紫外线辐射量大;紫外线辐射强度与总云量呈反相关,与能见度呈正相关,与气温呈正相关,与相对湿度呈反相关.     

商丘市紫外线辐射与气象因子的关系

利用2003年4月至2006年6月商丘太阳紫外线辐射强度资料及气象资料,分析了商丘市紫外线辐射的月、日变化规律及气象因子对紫外线辐射的影响。结果表明:商丘紫外线辐射月际分布是,年初、年底辐射量小,3~9月辐射量大,最大辐射指数为11.4;紫外线辐射的日变化规律显著,基本上遵循正态分布,呈抛物线型变化,早晚辐射量小、中午前后紫外线辐射量大;紫外线辐射强度与总云量呈反相关,与能见度呈正相关,与气温呈正相关,与相对湿度呈反相关。     

湛江市地面太阳紫外线辐射观测及分析

利用湛江市气象观测站2006年3月～2007年2月的紫外线辐射资料及地面气象资料,分析了湛江市紫外线指数日变化和季节变化特征。结果表明,紫外线指数与总云量、低云量、日照时数、地面水平能见度、相对湿度有较好的相关性。运用多元线性回归、逐步回归方法,分析了紫外线的影响因子,发现太阳高度角、总云量、地面水平能见度和日照时数,是影响湛江市紫外线辐射强度的关键因素,通过信度为0.05的F检验,发现拟合方程对紫外线的趋势变化具有一定的能力。     

石家庄市紫外线与气象因子的相关分析及等级预报方程的建立

通过对2005年1月至2007年12月石家庄市3a来紫外线实况资料和地面常规观测资料的分析,发现紫外线强度与中午时段的能见度、相对湿度、总云量、低云量、气温、风速6个气象因子有密切关系,其中,它与总云量的关系最为密切,其次是相对湿度。紫外线与相对湿度、总云量、低云量为负相关;紫外线与风速、气温、能见度呈正相关,并且在不同的月份与气温的相关性有明显的变化。利用多元回归分析方法,得出紫外线等级预报方程,为紫外线的预报提供了指导意义。     

呼和浩特市紫外线辐射强度变化特征及相关因子分析

通过对2005年6月至2006年5月期间的紫外线辐射强度监测资料和同期太阳总辐射量、云量、相对湿度资料的统计分析,研究了紫外线辐射强度的变化特征及与相关气象因子的关系。指出紫外线辐射强度具有明显的季节变化,夏季最强,冬季最弱。紫外线辐射强度日变化有明显规律,日最大值出现时间多集中在12—14时。紫外线辐射强度与太阳总辐射量呈明显正相关,与云量、相对湿度呈明显负相关。     

菏泽市紫外线辐射变化特征及月预报方程

利用2008年4月至2012年12月菏泽市紫外线观测资料以及地面常规气象观测资料和空气质量资料,分析了该地区太阳紫外线辐射的变化特征及其与各因子的相关关系,并建立逐月预报方程。结果表明:菏泽紫外线辐射年总量达到187.98 W/m2,春夏两季明显高于秋冬两季,5月达到全年的最大值,1月为全年的最小值;3~9月紫外线辐射极大值均可达到5级,其他月份均可达到4级。不同天气条件下紫外线辐射强度存在明显差异,其中晴天紫外线辐射强且稳定,呈抛物线变化;多云天紫外线辐射波动较大,时强时弱;阴天紫外线辐射相对较弱。紫外线辐射强度与风速、能见度、气温呈正相关,与总云量、低云量、相对湿度呈负相关,与SO2、PM10、NO2、PM2.5多呈负相关。基于多元线性回归分析向后剔除变量方法得出的逐月预报方程,经检验总体预报效果较好,对当地紫外线等级预报工作具有参考意义。     

阿拉善高原近40a总云量变化特征分析

利用阿拉善高原近40a(1971—2010年)观测年及四季平均总云量,分析其时空变化特征及Hurst指数,并对总云量与降水量、平均气温、日照时数及相对湿度等因子之间的关系进行分析。结果表明:(1)阿拉善高原近40a平均总云量在38.3%~45.8%之间;北部地区年平均总云量减少趋势显著,南部地区呈不明显的减少趋势。(2)年平均总云量与相对湿度呈显著正相关,与降水量、日照时数、平均气温相关不显著。春季、秋季和冬季总云量与降水、相对湿度呈显著正相关,与日照时数显著负相关,与平均气温相关性不显著。夏季总云量和降水量相关不显著,与相对湿度呈显著的正相关,与日照时数和平均气温呈显著的负相关。(3)Hurst指数分析显示,阿拉善高原北部地区年平均总云量、南部地区春季总云量、东北地区夏季总云量未来将显著减少,其余地区年及四季总云量的减少趋势不显著。     

紫外线辐射特征及影响因素分析

对太原市2002~2004年紫外线观测资料进行统计分析结果发现:紫外线辐射具有正午强早晚弱,夏季强冬季弱的特点;紫外线大值出现时间夏季明显早于冬季;通过与同时段气象因素对比分析,揭示了云状和云量、气压、能见度、湿度、空气污染对紫外线辐射的不同影响程度;紫外线辐射占太阳总辐射百分比具有冬季少夏季多和有云时非同比衰减的特点。紫外线的预报还要注重最大半小时平均值的预报,以预估紫外线对人体的最大可能伤害程度。     

郑州地区紫外线辐射强度变化规律分析

由于地球自转和公转的原因,太阳紫外线辐射强度呈现出以一年和一天为周期的规律性变化.一年之内,以夏季最强,冬季最弱;一天之内,中午前后最强,早晚最弱.影响紫外线辐射强度的因子比较多,最主要的是云量、云状和能见度.经分析,紫外线辐射强度随着云量的增加而减小,随着能见度的增大而增强;高云对紫外线辐射强度影响较小,低云影响较大,中云居中.通过研究,确定了它们之间的定量关系.     

Influences of the clearness index on UV solar radiation for two locations in the Tibetan Plateau-Lhasa and Haibei

Ultraviolet （UV） solar radiation has a significant influence on human health, the environment and climate. A series of measurements, including UV radiation （290 400 nm） and global solar radiation （Rs）, were continuously recorded from August 2004 at the Lhasa and Haibei sites on the Tibetan Plateau. Both observation sites＇ altitudes are above 3000 m and have similar meteorological conditions. The data from 2005 2006 was used to identify the varying characteristics of UV radiation. It＇s relation to the clearness index Ks, the relative optical mass mr, and Rs were established. The annual mean values of total daily UV radiation are 0.92 and 0.67 MJ m^-2 at Lhasa and Haibei, respectively. The UV radiation in Lhasa represented 4.6% of the global solar radiation while in Haibei this percentage was 4.2%. In the case of clear days （Ks 〉 0.8）, these percentages ranged between 4.0% and 4.5% in Lhasa and between 5.1% and 5.5% in Haibei. In the case of cloudy days （Ks 〈 0.4）, these percentages ranged from 4.4% to 6.8% in Lhasa and from 5.1% to 5.5% in Haibei. The maximum values of UV radiation for each relative optical mass diminished exponentially with mr. Thus, for Lhasa and Haibei, UV=46.25mr-129, and UV=51.76mr-142, respectively. The results of this study can be used to obtain more UV radiation data for the study of UV climate characteristics, the effects of UV on ecological processes and the feedback of the thinning of the stratospheric ozone, from more routine measurements Rs data.     

拉萨地区生物有效紫外辐射初步分析

根据1996～1998年由NILUV紫外辐射仪在西藏拉萨地区观测的紫外辐射资料,分析了青藏高原拉萨地区生物有效辐射的分布特征.结果表明,1997年日正午最大生物有效紫外辐射剂量率(UV dose rate)达到500mW m-2,最小值为9.7 mW m-2;晴天时生物有效辐射剂量率的日变化呈规则曲线,且早晚小,中午大;一年中紫外辐射变化的总趋势是由太阳天顶角决定的,紫外辐射的日变化和年变化是其最主要、最基本的变化;西藏拉萨地区的月平均红斑辐射剂量明显高于全球其他同纬度地区.     

Two Ultraviolet Radiation Datasets that Cover China

Ultraviolet(UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.     

Influence of natural and anthropogenic activities on UV Index variations – a study over tropical urban region using ground based observations and satellite data

Measurements of total ozone column and solar UV radiation under different atmospheric conditions are needed to define variations of both UV and ozone and to study the impact of ozone depletion at the Earth’s surface. In this study, spectral and broadband measurements of UV-B irradiance were obtained along with total ozone observations and aerosol optical depth measurements in the tropical urban region of Hyderabad, south India. We specifically used an Ultra-Violet Multifilter Rotating Shadow band Radiometer (UVMFR-SR), to measure UV irradiance in time and space. To assess the aerosol and O₃ effects on ground-reaching UV irradiance, we used measurements from a Microtops II sun photometer in addition to the Tropospheric Ultraviolet Visible radiation (TUV) model. We also assessed the Defense Meteorological Satellite Program – Operational Line Scanner (DMSP-OLS) night time satellite data for inferring biomass burning fires during the study period. Results clearly suggested a negative correlation between the DMSP-OLS satellite derived fire count data and UVMFR-SR data suggesting that aerosols from biomass burning are directly attenuating UV irradiance in the study region. Also, correlation analysis between UV index and ozone measurements from sun photometer and TOMS-Ozone Mapping Instrument (OMI) indicated a clear decrease in ground reaching UV-B irradiance during higher ozone conditions. The higher levels are attributed to photochemical production of O₃ during the oxidation of trace gases emitted from biomass burning. Results also suggested a relatively high attenuation in UV irradiance (~6% higher) from smoke particles than dust. We also found a relatively good agreement between the modeled (TUV) and measured UV irradiance spectra for different atmospheric conditions. Our results highlight the factors affecting UV irradiance in a tropical urban environment, south India.     

Characteristics of UV radiation at Tazhong of the Tarim Basin,west China

Tazhong station, located at the hinterland of the Taklimakan Desert in northwest China, experiences frequent dusty weather events during spring and summer seasons (its dusty season) caused by unstable stratified atmosphere, abundant sand source and strong low-level wind. On average, it has 246.2 dusty days each year, of which 16.2 days are classified as sand and dust storm days. To better understand the characteristic of solar ultraviolet (UV) radiation and factors influencing its variations under such an extreme environment, UV radiation data were collected continuously from 2007 to 2011 at Tazhong station using UVS-AB-T radiometer by Kipp and Zonen. This study documents observational characteristics of the UV radiation variations observed during the five-year period. Monthly UV radiation in this region varied in the range of 14.1–37.8 MJ m^?2 and the average annual amount was 320.7 MJ m^?2. The highest value of UV radiation occurred in June (62.5 W m^?2) while the lowest one in December (29.3 W m^?2). It showed a notable diurnal cycle, with peak value at 12:00–13:00 LST. Furthermore, its seasonal variation exhibited some unique features, with averaged UV magnitude showing an order of summer > spring > autumn > winter. The seasonal values were 37.0, 29.1, 24.9 and 15.9 MJ m^?2, respectively. In autumn and winter, its daily variations were relatively weak. However, significant daily variations were observed during spring and summer associated with frequent dust weather events occurring in the region. Further analysis showed that there was a significant correlation between the UV radiation and solar zenith angle under different weather conditions. Under the same solar zenith angle, UV radiation was higher during clear days while it was lower in sand and dust storm days. Our observations showed that there was a negative correlation between UV radiation and ozone, but such a relationship became absent in dusty days. The UV radiation was reduced by 6 % when cloud amount was 1–4 oktas, by 12 % when the cloud amount was 5–7 oktas, and by 24 % when the cloud amount was greater than 8 oktas. The relative reduction of UV radiation reached 26, 38, and 45 % in dust day, blowing sand day and sand and dust storm day, respectively. The results revealed that decrease in UV radiation can be attributed to cloud coverage and dust aerosols. Moreover, the reduction of UV radiation caused by dust aerosols was about 2–4 times greater than that caused by cloud coverage. These observational results are of value for improving our understanding of processes controlling UV radiation over sand desert and developing methods for its estimation and prediction.     

紫外辐射增强对菠菜种子萌发及出苗的影响

研究了紫外辐射（UA－B）增强对圆叶和尖叶菠菜种子萌发出苗的影响，结果表明，UV－B辐射增强将显著降低圆叶菠菜种子的出牙率和出苗率，延缓发牙进程，出苗速度，影响幼长势，而对尖叶菠菜的影响较小，增强UV－B辐射还能有效抑制菠菜种子发牙时因病菌感染而发生的霉变，并减少幼苗期病虫害的蔓延和发展。     

山东禹城紫外辐射变化特征及其估测方程的建立

本文对2005～2011年山东禹城地区观测得到的紫外辐射的时间变化特征及紫外辐射与总辐射比值的变化特征进行了分析, 并结合气温、降水和露点温度资料建立了禹城地区的紫外辐射估测方程。结果表明:紫外辐射日累计值的变化范围为0.10～1.20 MJ m-2 d-1, 年平均值为0.468 MJ m-2 d-1;紫外辐射日、季节变化规律与总辐射一致, 季节变化都表现为冬季小夏季大, 最小值出现在1月, 最大值出现在6月, 日变化则呈现早晚小中午大的特征;紫外辐射与总辐射的比值范围为0.023～0.046, 其季节变化特征也是冬季小夏季大, 该比值随晴空指数的增大而减小, 而在晴空指数大于0.5时比较稳定。利用温度日较差(日最高气温与最低气温的差值)建立了紫外辐射估测方程, 决定系数R2达0.80, 平均相对误差为0.19, 估测紫外线等级与实测紫外线等级相差不大于1的数据占95%, 该方法可以较好地进行紫外辐射等级的估测。