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1.
A rocket-borne solar middle ultraviolet photometer has been developed at the Physical Research Laboratory, Ahmedabad for the measurement of ozone concentrations at stratospheric and mesospheric heights. The instrument has now been flown successfully several times from thumba and ozone concentrations determined over an altitude range of 15 to 80 km. This paper describes the instrumentation, data analysis technique as well as the laboratory calibration procedures. Also presented are the results from four successful rocket experiments conducted during equinoctial months under an Indo-USSR collaborative programme for strato-mesospheric studies. The results show that at Thumba peak ozone concentrations vary between 2·2 and 3·1×1012 molecules per cc and the peak altitude varies from 25 to 29 km from flight to flight. In the altitude region above about 40 km the ozone concentrations over Thumba are lower than the standard mid-latitude model values, by a factor lying between 1·5 and 2·5. 相似文献
2.
北京上空大气臭氧垂直分布的特征 总被引：10，自引：1，他引：9
利用我国自行研制的探空仪和地面接收设备首次较系统地获得了北京地区连续一年（2001年 3月至2002年 2月）的大气臭氧垂直分布资料。结果分析表明：①北京地区上空臭氧浓度极大值的季节均值的变化范围为15．1～16．7 mPa,其高度位于20．7～25．1km之间,极小值的季节均值的变化范围为 2．0～2．8 mPa,其高度在对流层顶附近。②边界层和平流层下部是臭氧浓度变化的活跃区域,并具有明显的季节变化,在边界层内夏季臭氧积分浓度高于冬季相应值的 1．7倍之多,而在平流层下部,冬季臭氧积分浓度则高于夏季的相应值。夏季边界层中臭氧浓度偏高,表明臭氧是北京地区夏季重要的污染气体之一。③北京上空臭氧垂直廓线的形态呈多样性,夏秋季节以单峰为主,冬春季节经常出现双峰和多峰结构;次峰出现的区域一般在10～18km高度范围内。 相似文献
3.
中国大气臭氧探空仪的研制和应用 总被引：9，自引：1，他引：9
地球大气中的臭氧一直是全球气候和环境变化研究中的重要内容。大气臭氧探空系统是当前直接获得地球大气臭氧垂直结构资料的直接探测系统，同时也是为卫星臭氧探测和激光雷达臭氧探测等提供对比和定标的有力手段。中国大气臭氧探空仪的研制工作起步较晚且进展缓慢，这在一定程度上妨碍了中国大气臭氧高空探测业务化的进程。首次报道了中国大气臭氧高空探测业务化进展状况，重点报告中国自行研制的大气臭氧探空仪的结构和技术性能指标，讨论了中国大气臭氧探空仪主要技术性能指标与芬兰Vaisala臭氧探空仪的比对结果，并给出该系统在北京、南极等地区应用施放中所得到的部分探测结果。同时对中国大气臭氧高空探测业务化方面的近期任务提出了建议。 相似文献
4.
Sophie Godin-Beekmann 《Comptes Rendus Geoscience》2010,342(4-5):339-348
This article provides an overview of the various satellite instruments, which have been used to observe stratospheric ozone and other chemical compounds playing a key role in stratospheric chemistry. It describes the various instruments that have been launched since the late 1970s for the measurement of total ozone column and ozone vertical profile, as well as the major satellite missions designed for the study of stratospheric chemistry. Since the discovery of the ozone hole in the early 1980s, spatial ozone measurements have been widely used to evaluate and quantify the spatial extension of polar ozone depletion and global ozone decreasing trends as a function of latitude and height. Validation and evaluation of satellite ozone data have been the subject of intense scientific activity, which was reported in the various ozone assessments of the state of the ozone layer published after the signature of the Montreal protocol. Major results, based on satellite observations for the study of ozone depletion at the global scale and chemical polar ozone loss, are provided. The use of satellite observations for the validation of chemistry climate models that simulate the recovery of the ozone layer and in data assimilation is also described. 相似文献
5.
6.
《Comptes Rendus Geoscience》2018,350(7):354-367
In the 1980s, ground-based monitoring of the ozone layer played a key role in the discovery of the Antarctic Ozone Hole as well as in the first documentation of significant winter and spring long-term downward trends in the populated mid-latitude regions. The article summarizes the close-to-hundred-year-long history of ground-based measurements of stratospheric ozone, and more recent observations of constituents that influence its equilibrium. Ozone observations began long before the recognition of the impact of increasing emissions of manmade ozone-depleting substances on ozone and therefore on UV levels, human health, ecosystems and the Earth climate. The historical ozone observations prior to 1980s are used as a reference for the assessments of the state of the ozone layer linked to the enforcement of the Montreal Protocol. In this paper, we describe the worldwide monitoring networks and their ozone observations used to determine long-term trends with an accuracy of a few percent per decade. Since 1989, the ground-based monitoring activities have provided support for the amendments of the Montreal Protocol (MP). They include monitoring of (a) the ozone total column and the vertical distribution at global scale, (b) the ozone-depleting substances (ODS) related to the MP such as chlorofluorocarbons (CFCs), and their decomposition products in the stratosphere, and (c) the atmospheric species playing a role in ozone depletion, e.g., nitrogen oxides, water vapor, aerosols, polar stratospheric clouds. We highlight important accomplishments in the atmospheric monitoring performed by the Global Atmosphere Watch program (GAW) run under the auspices of the World Meteorological Organization (WMO) and by the Network for the Detection of Atmospheric Composition Change (NDACC). We also address the complementary roles of ground-based networks and satellite instruments. High-quality ground-based measurements have been used to evaluate ozone variabilities and long-term trends, assess chemistry climate models, and check the long-term stability of satellite data, including more recently the merged satellite time-series developed for the detection of ozone recovery at global scale, which might be further modified by climate change. 相似文献
7.
《地学前缘(英文版)》2022,13(2):101318
We present interesting application of artificial intelligence for investigating effect of the COVID-19 lockdown on 3-dimensional temperature variation across Nigeria (2°–15° E, 4°–14° N), in equatorial Africa. Artificial neural networks were trained to learn time-series temperature variation patterns using radio occultation measurements of atmospheric temperature from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). Data used for training, validation and testing of the neural networks covered period prior to the lockdown. There was also an investigation into the viability of solar activity indicator (represented by the sunspot number) as an input for the process. The results indicated that including the sunspot number as an input for the training did not improve the network prediction accuracy. The trained network was then used to predict values for the lockdown period. Since the network was trained using pre-lockdown dataset, predictions from the network are regarded as expected temperatures, should there have been no lockdown. By comparing with the actual COSMIC measurements during the lockdown period, effects of the lockdown on atmospheric temperatures were deduced. In overall, the mean altitudinal temperatures rose by about 1.1 °C above expected values during the lockdown. An altitudinal breakdown, at 1 km resolution, reveals that the values were typically below 0.5 °C at most of the altitudes, but exceeded 1 °C at 28 and 29 km altitudes. The temperatures were also observed to drop below expected values at altitudes of 0–2 km, and 17–20 km. 相似文献
8.
Although the basic physical relationships between various remotely sensed signatures and soil are sound, the representativeness of pixel-averaged wetness used to interpret the remotely sensed data is often suspect and at times even doubtful. To study the affect of local variation in soil moisture on the large-area average, mean areal precipitation, temperature and modelled soil moisture in 1/4° grid cells were analyzed for a 700 km by 400 km region in the US Southern Great Plains. Variability in five years of mean daily grid cell data was investigated for 150 km2 study sites, approximately corresponding in size to a satellite microwave pixel. The number of wetted grid cells and the magnitude of precipitation in grid cells within a site were highly variable. The variability of each of these factors is critical, and will not only influence mean site wetness, but also how the area will be seen from space. Analysis indicated that similar mean site precipitation values may result from numerous widely differing combinations of precipitation magnitude and watted gric cell population. Consequently, mean site moisture is also highly variable in the distribution and magnitude of the individual cell moisture values. Extreme values in several grid cells may severely bias the quadrant mean, while influencing a remote measurement much less. Although large-scale surface wetness may eventually be reliably inferred from satellite measurements, a degree of uncertainty will always exist, especially in semi-arid areas. One may be required to associate mean soil moisture with an expected distribution of wetness within a pixel. 相似文献
9.
Nandita D. Ganguly 《Journal of Earth System Science》2008,117(1):79-82
The Indian reserve of coking coal is mainly located in the Jharia coal field in Jharkhand. Although air pollution due to oxides
and dioxides of carbon, nitrogen and sulphur is reported to have increased in this area due to large-scale opencast mining
and coal fires, no significant study on the possible impact of coal fires on the stratospheric ozone concentration has been
reported so far. The possible impact of coal fires, which have been burning for more than 90 years on the current stratospheric
ozone concentration has been investigated using satellite based data obtained from Upper Atmospheric Research Satellite (UARS
MLS), Earth Observing System Microwave Limb Sounder (EOS MLS) and Ozone Monitoring Instrument (OMI) in this paper. The stratospheric
ozone values for the years 1992–2007, in the 28–36 km altitude range near Jharia and places to its north are found to be consistently
lower than those of places lying to its south (up to a radius of 1000 km around Jharia) by 4.0–20%. This low stratospheric
ozone level around Jharia is being observed and reported for the first time. However, due to lack of systematic ground-based
measurements of tropospheric ozone and vertical ozone profiles at Jharia and other far off places in different directions,
it is difficult to conclude strongly on the existence of a relationship between pollution from coal fires and stratospheric
ozone depletion. 相似文献
10.
《Comptes Rendus Geoscience》2018,350(7):432-434
NASA has a long and significant history in observations and data analysis research for understanding the short- and long-term changes in ozone in the atmosphere. For nearly 40 years, NASA has overseen satellite observations of stratospheric ozone. These observations have been augmented by ground-based remote sensing, balloon borne, and aircraft observations of ozone and ozone-related species and by continuous observations of ozone depleting substances. Together, they form the evidential basis for understanding ozone changes over these past four decades. Also, NASA has continuously funded laboratory, modeling and data analysis activities to better understand the observations obtained by NASA and other programs. NASA has plans to continue these activities in the future, at a level consistent with available funding, other Earth Science observational priorities, and more importantly, with a goal of ensuring that data exist to understand changes in ozone in the future as the abundances of ozone depleting substances decrease and those of greenhouse gases increase. 相似文献
11.
S. Fadnavis S. Dhomse S. Ghude U. Iyer P. Buchunde S. Sonbawne P. E. Raj 《International Journal of Environmental Science and Technology》2014,11(2):529-542
Ozone trends in the Upper Troposphere and Lower Stratosphere over the Indian region are investigated using three satellite data sets namely Halogen Occultation Experiment (1993–2005), Stratospheric Aerosol and Gas Experiment (1993–2005) II, and Aura Microwave Limb Sounder (MLS, 2005–2011). Estimated ozone trends using multi-variate regression analysis are compared with trends at two Indian ozonesonde stations (Delhi, 28°N, 77°E and Pune, 18°N, 73°E), and a 3-D Chemical Transport Model (CTM, SLIMCAT) for the 1993–2005 time period. Overall, all the observational data sets and model simulations indicate significant increasing trend in the upper troposphere (0–2.5 %/year). In the lower stratosphere, estimated trends are slightly positive up to 30 mb and are negative between 30 and 10 mb. Increasing trends in the upper troposphere is probably due to increasing trends in the tropospheric ozone precursor gases (e.g. CO, NO x , NMHCs). Here, we argue that these contrasting ozone-trend profiles might be partially responsible for insignificant long-term trends in the tropical total column ozone. On seasonal scale, positive trends are observed during all the seasons in the upper troposphere while structure of trend profile varies in lower stratosphere. Seasonal variations of ozone trends and its linkages with stratospheric intrusions and increasing trends in lightning flashes in the troposphere are also discussed. 相似文献
12.
《Comptes Rendus Geoscience》2018,350(7):341-346
The comprehensive investigation of polar ozone photochemistry and dynamics has required data obtained from as full a complement of available platforms as possible (ground-based, balloon, aircraft, and satellites). Perhaps the most detailed process studies have been conducted using measurements from aircraft, taking advantage of their targeting capabilities coupled with the potential for enabling measurements at high spatial and temporal resolution. The US National Aeronautics and Space Administration (NASA) conducted the first airborne science investigation of polar ozone in an effort to establish the causes of the recurring seasonal depletion of the Earth's stratospheric ozone layer over Antarctica that was identified in the mid-1980s. Subsequent airborne studies in the polar regions of both hemispheres benefitted from extensive successful collaborations among international scientists and the integration of the aircraft measurements with those obtained using ground-based, balloon-borne, and satellite instruments. This article provides an historical perspective of NASA's utilization of its airborne assets to advance our understanding of the chemical and physical processes that control the abundance of stratospheric ozone in both the Antarctic and Arctic. 相似文献
13.
Redistribution of dust particles in the ionosphere as a result of vortical motions is discussed. The following possibilities
are studied: capture and evolution of dust particles in acoustic-gravitational (AG) vortices, formation of dust vortices as
a result of involving a great number of dust particles into vortex motions, and formation of vertical dust flows (streamers).
It is shown that excitation of AG-vortices at altitudes of 110–130 km as a result of development of AG-wave instability, associated
with non-zero balance of heat fluxes, owing to solar radiation, water vapors condensation, infrared emission of the atmosphere,
and thermal conductivity, leads to a substantial transportation of dust particles and their mixing at altitudes of 110–120
km. Layers of dust particles in the ionosphere with a thickness of about a kilometer, forming at altitudes less than 120 km,
distribute within the region of existence of AG-vortical structures. As a result, at altitudes of 110–120 km, dust vortices
can appear, and transportation of particles up to altitudes of 130 km becomes possible. One of the ways of transportation
of dust particles in the ionosphere is vertical flows (streamers), which are generated by dust vortices as a result of development
of parametric instability. 相似文献
14.
Solar cycle and equatorial stratopause temperature 总被引：1，自引：0，他引：1
Variations in a solar activity and their effect if any on the temperature of the stratopause are studied. Monthly mean stratopause temperatures during 1969–1976 and departures from the monthly mean value of eight-year period, determined for four equatorial rocket launching stations,viz. Ascension Island, Kwajalem, Fort Sherman and Thumba, are statistically compared with sunspot number departures. To study the effects of seasonal variation on stratopause temperature, the data have been divided into winter, summer and equinoctial periods. Seasonwise study indicates that the correlation between the stratopause temperature and sunspot number is positive and just below the significant level for Thumba and positive and highly significant over all the other stations with a better relationship in equinoctial periods than in both winter and summer. The estimated regression coefficients are positive and significant. 相似文献
15.
The weather systems that predominantly affect the eastern and northeastern parts of India during the pre-monsoon summer months
(March, April and May) are severe thunderstorms, known as Nor’westers. The storms derive their names from the fact that they
frequently strike cities and towns in the southern part of West Bengal in the afternoon from the north-west direction while
traveling far from its place of genesis over the Bihar plateau. The storms are devastating in nature particularly due to strong
(gusty) winds, heavy rains and hails associated with it. Although these storms are well known for its power of causing damages,
studies on them are relatively few due to their small size and sparse network of observations. To address this important issue,
the evolution of two Nor’westers of 12 March and 22 May 2003 over Kolkata is studied in detail in this paper using hourly
Doppler weather radar (DWR) observations and high resolution Meteosat-5 imageries. In addition, supporting meteorological
reports are used to find the large scale conditions that influence the moisture convergence and vertical wind shear. The genesis
of both the storms is found to be over Bihar-Jharkhand region and beyond the range of the DWR. The satellite observations
are found to be useful in identifying the location and initiation of the storms. The movements of the storms are captured
by the DWR estimated vertical cross-section of reflectivities. The Doppler estimate shows that the 12 March storm had a vertical
extent of about 10–12 km at the time of maturity and that of 22 May reaching up to 18 km signifying deep convection associated
with these events. The genesis, maturity and dissipation are well brought out by the hourly DWR and satellite imageries. The
DWR observations suggest that the systems move at a speed of 20–25 m/s. The DWR estimated precipitation shows a detailed spatial
distribution around Kolkata with several localized zones of heavy rain and this is found to be well supported by the nearby
station observations. This study establishes that DWR observations along with hourly satellite imageries are able to capture
the evolution of Nor’westers. The study also shows that the composite DWR-satellite information is a reliable tool for nowcasting
the location, time and path of movement of Nor’westers. Based on these observations, a conceptual model of the Nor’wester
is proposed. 相似文献
16.
P Jindal P K Thapliyal M V Shukla A K Mishra D Mitra 《Journal of Earth System Science》2014,123(6):1265-1271
The present study examines the potential of infrared sounder observations from Indian geostationary satellite INSAT-3D for the estimation of total column integrated ozone over the tropical Indian region. A dataset with diverse profiles was used to create training and testing datasets using forward simulations from a radiative transfer model for infrared sounder channels. A study was carried out for the standard tropical atmospheric profile to examine the sensitivity of ozone band radiance corresponding to the atmospheric temperature, water vapour, and ozone mixing ratios at different atmospheric pressure levels. Further, statistical retrieval technique has been used for the total column ozone estimation using two different approaches: (i) ozone channel observation along with the a-priori estimate of temperature and water vapour profile and (ii) only sounder channels observations. The accuracy of the retrieval algorithms was examined for different errors in the atmospheric profiles for the method (i) and different sensor noise specification for the method (ii). This study has shown that accurate temperature information is very important for ozone estimation and lower instrument noise results in better ozone estimates. 相似文献
17.
2008-2012年拉萨地基与卫星臭氧总量观测比较 总被引：1，自引：0，他引：1
通过比较2008-2012年拉萨站地基观测臭氧总量与三种卫星反演产品, 评估地基和卫星观测臭氧总量数据的质量信息. 结果表明: 地基与卫星臭氧总量绝对差为-10~15 DU, 相对差为-4%~4%, 日尺度相对差呈随机分布特征; TOSOMI算法反演的SCIAMACHY臭氧总量更接近地基观测结果, DOAS算法反演OMI臭氧总量与地基观测结果差异最大. 地基与卫星臭氧总量标准差存在季节性变化, 夏季最大, 冬季最小; 云的影响会加剧地基与卫星臭氧总量差异, 以SCIAMACHY产品最为显著. 相似文献
18.
R. Raghavarao R. Suhasini R. Sridharan B. V. Krishnamurthy O. P. Nagpal 《Journal of Earth System Science》1990,99(3):413-423
The equatorial wave campaign-II which formed a part of the Indian Middle Atmosphere Programme (IMAP), was conducted from SHAR
(13.7°N, 80.2°E) from 15 January to 28 February 1986. Winds were measured from ground to 60 km by means of high altitude balloon
and a meteorological rocket (RH-200), once everyday, for 45 days. The frequencies of the oscillations in the deviations of
the east-west component of the winds from its mean at each height with one kilometer interval were obtained by the maximum
entropy (ME) method and phases/amplitudes of these frequencies were determined by the least squares technique on the wind
variation time series. The ME method has the inherent advantage of providing periodicities up to 1.5 times the data length.
The height structure of the long period waves of > 23 day periodicities that have larger amplitudes nearly by a factor of
2 as compared to the medium (9 to 22 day) or shorter period (4 to 8 day) ones, reveal two height regions of enhanced amplitudes,
one in the troposphere and another in the upper stratosphere/lower mesosphere, that too, mostly in the regions of positive
(westerly increasing or easterly decreasing with height) wind shears. The waves are seen to be inhibited in the negative wind
shear regions. From the abrupt changes in the altitude variation of phase, the possible source region has been identified.
The vertical wavelengths have been estimated to be 34 km and 19 km in the troposphere and lower stratosphere respectively
and 8 km in the upper stratosphere and lower mesosphere. Around 56 km the wave amplitude is reduced to 1/4 of its value below,
while the vertical shear strength in the mean wind doubled up. The tropospheric waves are suggested to be Rossby waves of
extratropical origin penetrating to tropical latitudes. The stratospheric/mesospheric waves however appear to emanate from
a source around the stratopause. 相似文献
19.
Ali M. Al-Salihi 《Arabian Journal of Geosciences》2018,11(20):633
Aerosol optical depth (AOD), Angstrom exponent (AE), and ozone monitoring instrument aerosols index (OMI-AI) data, derived from MODerate Resolution Imaging Spectroradiometer (MODIS) and OMI sensor on board NASA’s Aqua satellite and NASA-Aura satellite platforms, have been analyzed and classified over Baghdad, Iraq, for an 8-year period (2008–2015). In order to give an obvious understanding of temporal inconsistency in the characteristics and classification of aerosols during each season separately, PREDE POM-02 sky radiometer measurements of AOD, carried out during a 2-year period (2014–2015), were compared with MODIS–Aqua AODs. On seasonal bases, MODIS–Aqua AODs corroborate well with ground-based measurements, with correlation coefficients ranging between 0.74 and 0.8 and RMSE ranging from 0.097 to 0.062 during spring and autumn seasons respectively. The overall satellite- and ground-based measurement comparisons showed a good agreement with correlation coefficients of 0.78 and RMSE of 0.066. These results suggest that MODIS–Aqua gives a good estimate of AOD. Analysis of MODIS–Aqua data for the 8-year period showed that the overall mean AOD, AE, and OMI-AI over Baghdad were 0.44?±?0.16, 0.77?±?0.29, and 1.34?±?0.33 respectively. AOD records presented a unique peak which was extended from mid-spring (April) to mid-summer (July) while the AE annual variability indicated a more complicated behavior with minimum values during the period from late spring (May) to early autumn (September). The maximum AOD and OMI-AI values occurred during summer while their minimum values occurred during winter. The AE showed an opposite behavior to that of AOD such that the highest AE values occurred during autumn and winter and the lowest values happened during spring and summer. This behavior may be attributed to the domination of coarse aerosol particles during autumn and winter seasons and fine aerosol particles during spring and summer seasons. A Hybrid Single-Particle Lagrangian Integrated Trajectory model was utilized to determine the source of air mass transport and to recognize the variability of aerosol origin regions. Finally, AOD, AE, and OMI-AI values have been employed to identify several aerosol types and to present seasonal heterogeneity in their contribution based on their origins. 相似文献
20.
Tsvetkov Yu. P. Kuznetsov V. D. Golovkov V. P. Brekhov O. M. Pelle V. A. Krapivnyi A. V. Nikolaev N. S. 《Doklady Earth Sciences》2011,436(1):117-121
The solution to the problem of extraction of the anomaly Earth’s magnetic field (EMF) from stratospheric balloon magnetic
surveys with the help of global analytical models of the normal EMF is proposed. In the problem solution, errors for the analytical
models of the normal EMF and its secular variation at a set moment of time are assessed; the found error is introduced as
a correction to the extracted anomaly EMF. The error of the model is determined in the places where significant magnetic anomalies
are absent. In this case, the error of the model corresponds to deviations of the normal EMF components, synthesized by coefficients
of analytical models, and to deviations of the EMF secular variations from the measured values at quite a low value of the
variable EMF or one being taken into account. These places are determined when carrying out additional measurements in vertical
gradients of the EMF with the use of scalar magnetometers at the gauge length of 6 km. It has been shown that the found places
can be considered as nonanomaly, if the difference of values of the anomaly EMF at the gauge length of 6 km does not exceed
1.5 nT within the profile’s portion of about 100 km in length. An experiment in nature has revealed that errors for the IGRF-2005
and IGRF-2010 models, corrected for secular variation of the EMF, can reach 200 and 140 nT, respectively, within the limits
of the territory where the Kama-Emba magnetic anomaly is located; these errors are determined by the considered causes. Comparison
of aerostatic profiles of magnetic anomalies with data on the anomaly EMF, derived from the maps, has shown that the realizations
derived from the maps contain overestimated negative values of the anomaly EMF, because they reflect processes in the near-surface
layer of the Earth’s crust. This fact causes the situation when attempts to recalculate the anomaly EMF into the upper half-space
by the near-surface data still have not been successful. Only realizations derived at the altitudes comparable to the thickness
of the Earth’s crust can give an adequate model of the anomaly EMF in the circumterrestrial space and enable us to recalculate
magnetic anomalies reliably into any altitude levels. 相似文献