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1.
利用2010年春夏之交石家庄地区11架次的气溶胶和云凝结核(CCN)飞机同步观测资料,对比分析该地区云天和晴天气溶胶粒子的垂直廓线、不同高度气溶胶数谱特征,以及CCN的垂直分布、活化特性等。结果表明:云天气溶胶数浓度均值为1 553.28 cm~(-3),有效直径均值为0.52μm,比晴天数浓度(883.82 cm~(-3))大76%,有效直径(0.37μm)大41%。云天气溶胶数浓度呈指数型递减分布,有效半径在2 500 m以下随高度变化不明显,2 500 m以上随高度逐渐增大。晴天气溶胶数浓度在800～1 500 m内有累积,有效半径随高度没有明显的变化趋势。不同高度上气溶胶谱型基本一致,云天和晴天在气溶胶小尺度端(0.3μm)谱分布是连续的,在0.3μm处数谱均明显下降。云天和晴天CCN数浓度均随高度增大而减小,且各个高度层上云天CCN数浓度均大于晴天。云天CCN活化比率随高度变化不明显,晴天CCN活化比率随高度增大。气溶胶粒子尺度与CCN活化比率之间呈线性正相关。 相似文献
2.
植物生理学研究表明:紫外线对纤维作物的品质有重要影响,上海植物生理研究所试验:用兰紫光培养的棉花比用红橙光培养的棉花产量低、品质差。气候和气象学研究证实:紫外线辐照度受太阳高度角、拔海高度、大气状况影响。其中太阳高度角又决定于地理纬度、季节和地方真太阳时间;大气状况主要是指云、气溶胶含量及水汽压强。新疆棉区地理纬度差达8度,拔海高度差1000m以上。大气状况:和田附近多浮尘天气,北疆阴雨天气较多,东疆多晴好天气。新疆棉区的这些显著差异,必造成各地紫外线辐照度的显著差异,而紫外线辐照度 相似文献
3.
利用河北省2005年10月份的3次气溶胶飞机观测资料和宏观天气资料,综合分析石家庄地区不同天气条件下气溶胶的垂直分布和尺度谱分布特征。分析结果表明:气溶胶浓度的分布与大气环境情况密切相关。气溶胶数浓度最大值的变化范围是103~104cm-3,平均数浓度为103cm-3,粒子平均直径为0.120~0.150μm;21日近地面有霾,相对湿度为58%,近地面气溶胶浓度较17和29日略低,但粒子平均直径(0.165μm)比其余两次要大,可见相对湿度较大,大气中水汽含量较多,有利于小粒子凝结水汽,使粒子直径增大;逆温层结下,粒子在逆温层下累积,无逆温时数浓度最大值出现在近地面附近。气溶胶粒子谱呈单峰分布。 相似文献
4.
利用2010年8月30日河北省石家庄一次霾天气条件下的气溶胶飞行探测资料,分析了石家庄地区上空658—6933 m高度范围内大气气溶胶粒子平均数浓度、平均直径的垂直分布特征和9个水平飞行高度上的谱分布特征。结果表明:轻度霾天气条件下的气溶胶平均数浓度为325个/cm3,平均直径为0.169μm。在约1000 m高度以下,气溶胶平均数浓度随高度的增加呈线性减少趋势。粒径也随高度增加而减小,由0.187μm减小至0.164μm。1000 m高度以上,气溶胶平均数浓度随高度减少趋势变缓,粒子平均直径在0.167~0.171μm范围内波动。9个不同高度上的谱分布都呈单峰型,随着高度增加,谱宽变小,峰值向小尺度方向移动。后向轨迹计算分析表明:污染气团的远距离输送可能是导致大气1500 m高度层气溶胶数浓度突增的原因。 相似文献
5.
气溶胶辐射效应在华东地区一次雾霾过程中的作用 总被引：3，自引：1，他引：2
利用WRF/Chem(Weather Research and Forecasting Model coupled with Chemistry)模拟了2013年12月华东地区一次雾、霾事件气溶胶辐射反馈效应对气象场和大气质量的影响。通过3个不同气溶胶浓度设置的试验区分气溶胶浓度不同辐射效应的影响。比较不同试验得出,本次雾、霾过程中,不论是气溶胶直接、半直接辐射效应还是间接效应均使污染地区短波辐射减少、2 m气温下降、大气边界层高度降低,不利于水汽与污染物的扩散,空气污染进一步加重,雾结构进一步稳定,并使雾的持续时间延长,发展高度更高;对于化学场来说,气溶胶直接、半直接辐射效应使污染地区PM_(2.5)浓度增大、消光系数增大、氮氧化物浓度增大,臭氧浓度降低;间接辐射效应使PM_(2.5)浓度和消光系数进一步增大,氮氧化物、臭氧浓度降低。综上所述,气溶胶辐射效应能使大气污染加重,并利于雾的发生、发展。 相似文献
6.
基于对植物生长季大气水汽氢氧稳定同位素组成(δ~(18)O、δD)的原位连续观测数据,研究了青海湖高寒湿地生态系统大气水汽氢氧稳定同位素特征以及大气水汽δ~(18)O与主要环境因子的相关关系。结果显示:大气水汽中δ~(18)O和δD在0.5 m和1.5 m以及0.9 m和1.9 m之间差异性都很小,且季节变化趋势都表现为生长季中期低,前期和后期高。降水量、温度、相对湿度、蒸散和净辐射都是影响大气水汽δ~(18)O变化的重要环境因子,且各环境因子之间存在相互联系协同作用的关系。受研究区环境因子、大气水汽来源以及青海湖蒸发水汽的影响,表征当地大气水汽δ~(18)O和δD相关关系的大气水汽线方程MVL偏离全球大气降水线方程GMWL。 相似文献
7.
《干旱气象》2016,(5)
根据河北邢台市2015年10月11—23日一次重污染天气过程的激光雷达探测数据,对大气污染物浓度和雷达反演得出的大气边界层(PBL)高度、气溶胶光学厚度(AOD)和消光系数的变化进行分析。结果表明:在剔除降水因子的影响后,PBL高度对PM_(2.5)浓度有显著影响,PBL高度越低,PM_(2.5)浓度越高,且两者的相关性夜间好于日间;大气污染物浓度的增加会导致AOD和气溶胶消光系数的显著升高,且AOD与PM_(2.5)浓度的相关性日间好于夜间,在降水的湿沉降效应和大气相对湿度增加的影响下,会出现大气污染物浓度下降,但AOD升高的现象;300 m高度的气溶胶消光系数与地面污染物浓度的日变化趋势较为一致,贴近地面处消光系数相对较小。整体而言,随着PBL高度下降、AOD上升和消光系数增加,环境大气质量逐步趋于恶化。 相似文献
8.
中国西部干旱地区太阳直接辐射通量密度与大气质量的关系 总被引：1，自引：0，他引：1
本文根据中国西部干旱地区大气物理状态(大气可降水量和大气浑浊度)的变化范围,利用太阳直接辐射通量密度的理论计算公式,计算了各种大气透明系数状况下的太阳直接辐射通量密度。计算结果表明,大气质量m=2时的透明系数P_2和m相同时,由于水汽和气溶胶的含量配置不同而引起太阳直接辐射通量密度的差异,在辐射日变程的主要时段(m=1-3)内并不大。于是得到各种透明系数P_2状况下太阳直接辐射通量密度随大气质量变化的平均关系。不同海拔高度比较,当透明系数P_2相同时,各自的大气物理状态虽然不同,但m相同时的太阳直接辐射通量密度基本相同。现有的表征太阳直接辐射通量密度值和大气质量联系的关系式都不能很好地描述计算结果。根据太阳直接辐射通量密度随大气质量变化的特性,我们提出了新的关系式。最后,整理了不同拔海高度和不同地理景观的四个日射站(西藏那曲、青海格尔木、甘肃敦煌和民勤)的多年观测资料。经验计算结果与观测值比较,一致性良好。 相似文献
9.
利用2010年11月6日在珠江三角洲的佛山、江门等地区上空进行的一次飞机探测数据,初步分析气溶胶粒子的垂直和水平分布特征。结果表明,气溶胶粒子在不同的高度有较大的差异,自下而上存在着累积层、递减层和增加层,在1 033 m以下的大气边界层存在气溶胶粒子的累积,气溶胶粒子最小浓度为1 151.15/cm3,高度1 033 m;最大浓度为7 307.38/cm3,高度627 m;平均浓度5 775.63/cm3,平均直径0.212 μm,最大直径0.219 μm,最小直径0.189 μm。在1 033 m以上,气溶胶粒子浓度随高度增加而递减,但在逆温层附近气溶胶粒子的浓度出现了随高度增加而增加的现象。在江门鹤山上空3 800 m的高度层平飞时段,气溶胶粒子数浓度平均为19.74/cm3,变化范围1.97～53.65/cm3。对不同高度粒子谱分析表明,其谱型为多峰型,且高度越高,谱宽越窄,大粒子基本集中在1 000 m高度以下。 相似文献
10.
本文提出了一种利用可见光与近红外大气窗区内的0.5μm和0.85μm双通道的组合,通过观测地气系统的反射辐射从卫星上遥感陆面上空气溶胶的方法.模拟试验发现,对于不同类型的气溶胶,随着气溶胶光学厚度的逐渐增大,0.5μm和0.85μm双通道的反射辐亮度的差值和比值呈现出明显不同的变化趋势,据此便可以识别出气溶胶的类型,并... 相似文献
11.
祁连山地形云试验区自然地理和气候特征 总被引：5，自引：2，他引：3
对祁连山地形云民乐试验区的降水时空变化及夏季降水、云和风向的日变化进行分析发现,试验区降水随海拔升高由北向南递增,在祁连…北坡实测最大年降水量511 mm,出现在海拔2500 m的瓦房城.全年7月降水最多,6～8月降水量占年降水量的57%.夏季风向日变化明显,以山谷环流为主,白天多为NW风.夜间为SSE风,午后谷风使水汽向祁连山北坡汇集,气流抬升形成对流云,故山区16:00～20:00降水频率最高,有两个雨峰分别出现在午后和半夜,与低云量和积云、积雨云的日变化对应.近50年的气候变化表明,年降水量呈上升趋势,春、夏、秋季降水量均为上升趋势,冬季则下降.1957～2004年有两个枯水期,两个丰水期,1998年至今处于丰水期.年降水量和年径流量最大熵谱图分析表明,4.8年和3年周期较显著,民乐年降水量和莺落峡年径流量熵谱图对应较好,还存在9年的振动周期. 相似文献
12.
In this study, two universal turbidity parameters, the Angstrom turbidity coefficient and Linke turbidity factor, are applied to study the atmospheric turbidity characteristics of Taichung Harbor. Meteorological parameter values were measured during 2004 and 2005 at the Wuchi weather station of the Taiwan Central Weather Bureau, near the Taiwan Strait. Results based on the Angstrom turbidity models (βLou, βPin, and βVis) indicated that annual mean values of the Angstrom turbidity coefficients were 0.174, 0.21 and 0.201, respectively. Four sets of Linke turbidity factors (TLin, TLou, TPin and TVis) were calculated using the original Linke method and the Dogniaux method, incorporating the computed Angstrom turbidity coefficients (βLou, βPin and βVis); the resultant values were 4.30, 6.40, 7.10 and 6.95, respectively. The monthly average values, frequency of occurrence, and cumulative frequency distributions were calculated using different models to describe the clear-sky atmospheric conditions at Taichung Harbor. The frequency results show that for over 50% of the dataset, three sets of Angstrom turbidity coefficients fell between 0.15 and 0.18, and four sets of Linke turbidity factors (TLin, TLou, TPin and TVis) fell between 4.0 and 6.5. Thus, for 50% of cloudless days, the sky can be between turbid and clear over Taichung Harbor. Furthermore, the results reveal that for 30% of the dataset, three Angstrom sets of turbidity coefficients (βLou, βPin, and βVis) exceed 0.2 and four sets of Linke turbidity factors (TLin, TLou, TPin and TVis) exceed 5.0. This indicates that 30% of cloudless sky conditions can be considered turbid to very turbid. 相似文献
13.
Summary We investigated the ratio of photosynthetically active photon flux (Q
p
) to global solar radiation (R
s
) at three sites along different altitudes in Naeba Mountain, Japan at various temporal scales based on 3 years measurement
data (1999–2001). The lowest values of the ratio ever reported were found for all sites on both an hourly and a daily scale.
A similar slight diurnal pattern was found for all sites based on the monthly mean hourly values of the ratio. However, different
sites exhibited different seasonal courses. Statistically significant altitude dependencies were found for the hourly Q
p
/R
s
under both clear and cloudy weather conditions (t-test, P < 0.001). For clear weather conditions, the hourly Q
p
/R
s
exhibited an increasing trend with altitude at an average rate of 3.6% per km. The increasing rate was more noticeable below
900 m (8.8% per km) than above (0.7% per km). The inverse trend was found for hourly Q
p
/R
s
with the altitude under cloudy weather conditions. The hourly Q
p
/R
s
decreased from 550 m to 1500 m at a rate of 1.8% per km. Again, a major decrease occurred below 900 m, which had the rate
of 4.2% per km, compared with 0.2% per km over 900 m. Although the same tendencies were noted for daily Q
p
/R
s
, under clear sky conditions, they were not as statistically significant as the hourly counterpart (t-test, P < 0.021). The
increasing rate of Q
p
/R
s
at this scale under clear weather conditions was near that of the hourly rate, but below the 900 m rate was reduced to near
half of the hourly rate (4.7% per km). And the rate over 900 m increased to 2.7% per km. On the other hand, statistically
significant altitude effect was noted for the daily under cloudy weather conditions (t-test, P < 0.002). A rapidly decreasing
rate was found for it along the altitude gradient. The reason was due to the large decreasing rate below 900 m (12.4% per
km). But again similar to the hourly Q
p
/R
s
, a very small decreasing rate of daily Q
p
/R
s
was found over 900 m under cloudy weather conditions. These results suggest the necessity of considering the altitude dependency
of Q
p
/R
s
in future studies. 相似文献
14.
采用西南地区巫溪大官山同一坡面10个不同海拔高度梯度观测站2019~2020年逐小时温湿观测资料,分析了气温、气温直减率、日较差和相对湿度的梯度变化特征。结果表明:观测期间,气温随海拔升高而降低,海拔2000 m以上区域秋、冬季常出现逆温或同温现象;年平均气温递减率为0.57℃/100 m,最大值出现在3月和9月,分别为0.63℃/100 m和0.62℃/100 m,2月最低为0.49℃/100 m;日较差总体随海拔升高而减小,但在海拔1065~1222 m,出现了日较差随海拔升高而快速下降的突变区;年、春季在海拔1222~2180 m,秋季在海拔1222~2550 m,出现了日较差相对稳定层,其它季节不太明显。在海拔1670 m以下区域,年相对湿度为78.5%,夏季最大（85.3%）,秋季次之（82%）,冬季再次（74.3%）,春季最低（72.3%）;随着海拔升高云雾出现频率增大,年和各季相对湿度均随之增大;海拔1670~1930 m为突变区间,相对湿度迅速增加,在海拔1930~2550 m,年、春、夏、秋季处于云中的时间较多,相对湿度变化不大;冬季由于云层低,海拔较高的区域常处于云的上方,相对湿度随海拔升高反而有所减小。 相似文献
15.
基于2019年1月~2020年12月西南地区东部大官山降水观测数据,分析了降水随海拔高度的变化特征。结果表明:2019~2020年,大官山降水量总体随海拔升高而增大,多年平均梯度变化率为1.32%/100 m,最大降水高度在海拔1900 m左右。各季降水梯度变化率中,夏、秋季高,冬、春季低,夏季为3.31 mm/100 m,秋季为1.39 mm/100 m,冬季为0.50 mm/100 m,春季为0.67 mm/100 m。各月降水梯度变化率中,7月最高,达5.06 mm/100 m,1月和11月最低,分别为0.23 mm/100 m和0.29 mm/100 m。降水日数和小雨日数随高度的线性变化趋势较明显,平均上升率分别为2.86 d/100 m和2.56 d/100 m。大雨日数在海拔1900 m左右最大,暴雨日数在海拔2500 m左右最大。降水日变化表现出多峰值特征,降水量和降水强度均在06~09时达到最大,降水频率也随海拔高度升高而增大,其中,高海拔降水频率在15时左右达到最大。降水随海拔高度的变化与天气过程密切相关,持续阴雨天气过程降水量的梯度变化较为平缓,暴雨天气过程降水量随海拔的升高而升高,局地阵雨中单次过程降水量与海拔高度相关性不明显。 相似文献
16.
H. D. Kambezidis A. K. Fotiadi B. D. Katsoulis 《Meteorology and Atmospheric Physics》2000,75(3-4):259-269
Summary This work studies the variability of the Linke (T
L
) and Unsworth-Monteith (T
U
) turbidity parameters in the urban atmosphere of Athens. Beam irradiance observations performed at the Actinometric Station
of the National Observatory of Athens are used in the period 1975–1995. This study examines (i) the inter-annual variation
of T
L
and T
U
, (ii) their mean seasonal variability, (iii) their monthly average variation, and (iv) their mean daily variation. Also,
for various air-mass origins, the mean seasonal variations of T
L
and T
U
are given. The frequency of occurrence of the parameters in various ranges is also shown. An innovative interpretation of
the impact of the Saharan dust on the radiative properties in the atmosphere of Athens is attempted.
Received May 19, 2000 Revised October 17, 2000 相似文献
17.
Summary The Linke T
L
, ?ngstr?m β and Unsworth-Monteith δ
a
turbidity parameters are investigated for two sites in Egypt: Cairo, a densely populated urban area, and Aswan, an arid unpolluted
area. These three turbidity parameters are calculated from broadband pyrheliometric measurements recorded hourly over the
period 1992–96. Monthly averages of T
L
, β and δ
a
show relatively flat and identical seasonal variations with a marked main maxima during spring at both sites, due to Khamsin
depressions coming from the Great Sahara. A secondary maximum is observed at Aswan in summer, due to dust haze which prevails
during that season, and at Cairo in autumn, due to the northern extension of the Sudan monsoon trough, which is accompanied
by small scale depressions with dust particles. Annual mean values of T
L
, β and δ
a
(5.59, 0.250 and 0.372, respectively) at Cairo are larger than at Aswan (3.89, 0.139 and 0.213, respectively). In the same
way, the seasonal mean values of T
L
, β and δ
a
at Cairo are larger than at Aswan. More generally, the monthly and yearly average turbidity values are significantly larger
in Cairo than in Aswan for the whole period 1992–96, which is attributable in part to the urbanization/industrialization effect
of Cairo. An estimate of the corresponding overburden is obtained by comparison between the present data and older T
L
data from 1922–27. It is also shown that turbidity over both sites is largest during 1992, just after the eruption of Mount
Pinatubo in 1991. The dependence of β on some meteorological parameters such as wind speed and direction, precipitable water,
relative humidity, temperature and visibility, is also analyzed. This reveals in particular that visibility is not a good
predictor of turbidity at either site. Conversely, the wind direction and speed have a definite effect on turbidity, and consequently,
largest turbidities occur when the wind carries aerosols from the main industrial particle source areas around Cairo. For
any season of the year, the average turbidity at the latter site is larger than that at other big cities such as Athens, Rome,
and Toronto, but is lower than at Dhahran, Saudi Arabia.
Received February 3, 2000 Revised August 25, 2000 相似文献
18.
不同生育期水分胁迫对玉米光合特性的影响 总被引：6，自引：0，他引：6
利用遮雨棚以夏玉米为对象进行水分胁迫大田试验,通过分析玉米叶片光合测量数据,研究不同生育期水分胁迫对玉米光合特性的影响,为定量分析不同水分胁迫程度对玉米生育的可能机理提供数据和初步的理论支持.结果表明:土壤水分下降会使玉米叶片的光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)降低,而胞间CO2浓度(Ci)和水分利用效率(WUE)会增加;Pn随着光照强度的增加而增加,且随着水分胁迫强度增强,Pn增加速率降低;干旱胁迫会改变Pn、Tr日变化规律,并且对拔节期光合作用的抑制小于成熟期;WUE与Pn存在极显著的正相关关系,与Tr、Ci及Gs存在显著的负相关关系. 相似文献
19.
Mossad El-Metwally 《Meteorology and Atmospheric Physics》2013,119(1-2):71-90
Long-term data from diffuse and global irradiances were used to calculate direct beam irradiance which was used to determine three atmospheric turbidity coefficients (Linke T L , Ångström β and Unsworth–Monteith δ a ) at seven sites in Egypt in the period from 1981 to 2000. Seven study sites (Barrani, Matruh, Arish, Cairo, Asyut, Aswan and Kharga) have been divided into three categories: Mediterranean climate (MC), desert Nile climate (DNC) and urban climate (UC, Cairo). The indirect method (i.e., global irradiance minus diffuse irradiance) used here allows to estimate the turbidity coefficients with an RMSE% ≤20 % (for β, δ a and T L ) and ~30 % (for β) if compared with those estimated by direct beam irradiance and sunphotometeric data, respectively. Monthly averages of T L , β and δ a show seasonal variations with mainly maxima in spring at all stations, due to Khamsin depressions coming from Sahara. Secondary maxima is observed in summer and autumn at DNC and MC (Barrani and Arish) stations in summer due to dust haze which prevails during that season and at UC (Cairo) in autumn, due to the northern extension of the Sudan monsoon trough, which is accompanied by small-scale depressions with dust particles. The mean annual values of β, δ a , and T L (0.216, 0.314, and 4.6, respectively) are larger in Cairo than at MC stations (0.146, 0.216, and 3.8, respectively) and DNC stations (0.153, 0.227, and 3.8, respectively). Both El-Chichon and Mt. Pinatubo eruptions were examined for all records data at MC, UC and DNC stations. The overburden caused by Mt. Pinatubo’s eruption was larger than El-Chichon’s eruption and overburden for β, and T L at DNC stations (0.06, and 0.58 units, respectively) was more pronounced than that at MC (0.02, and 0.26, respectively) and UC (0.05 and 0.52 units, respectively) stations. The annual variations in wind speed and turbidity parameters show high values for both low and high wind speed at all stations. The wind directions have a clear effect on atmospheric turbidity, and consequently, largest turbidities occur when the wind carries aerosols from the main particle sources, such as industrial particle sources around Cairo or to some extent from the Sahara surrounding all study stations. 相似文献
20.
The analysis of time series of the Linke turbidity factors is performed for the atmosphere mass m = 2 (T
2) and atmospheric aerosol optical thickness for the wavelength λ0 = 0.55 μm (AOT) from the data of 14 actinometrical stations of Central Siberia and Trans-Baikal territory. It is shown that
over the period from 1976 to 2006, the increased atmospheric transparency is observed in the region. Quantitative estimates
of changes in multiyear mean annual variations of T
2 and AOT at different periods of averaging and for different time periods are derived. 相似文献