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1.
Solar proton events (SPEs) are known to have caused changes in constituents in the Earth’s polar neutral middle atmosphere. The past four years, 2000–2003, have been replete with SPEs. Huge fluxes of high energy protons entered the Earth’s atmosphere in periods lasting 2–3 days in July and November 2000, September and November 2001 and October 2003. The highly energetic protons produce ionizations, excitations, dissociations and dissociative ionizations of the background constituents, which lead to the production of HOx (H, OH, HO2) and NOy (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The HOx increases lead to short-lived ozone decreases in the polar mesosphere and upper stratosphere due to the short lifetimes of the HOx constituents. Large mesospheric ozone depletions (>70%) due to the HOx enhancements were observed and modeled as a result of the very large July 2000 SPE. The NOy increases lead to long-lived stratospheric ozone changes because of the long lifetime of the NOy family in this region. Polar total ozone depletions >1% were simulated in both hemispheres for extended periods of time (several months) as a result of the NOy enhancements due to the very large SPEs.  相似文献   

2.
The LIMS experiment was launched on the Nimbus 7 satellite for the purpose of sounding the vertical structure of temperature and key upper atmosphere trace gases on a global scale. The technique of thermal infrared limb sounding was used to obtain measurements of O3, H2O, NO2, and HNO3. LIMS collected data almost continuously from late October to late May over the latitude range from 64°S to 84°N. Two of the gases, NO2 and HNO3, are important elements in the NOx chain of chemical reactions leading to ozone destruction. We will describe results for these gases in terms of zonal mean profiles and latitudinal distributions. The period selected for study is January–May 1979, when a major stratospheric warming occurred.  相似文献   

3.
The Meteorology Department of India has been measuring vertical column density of NO2 at Maitri (70.7°S, 11.7°E), Antarctica since July 1999 using a Mark IV, Brewer Ozone Spectrophotometer. Maitri is situated at the south of the Antarctic circle. An analysis of 6 years of data shows that NO2 column has seasonal variation with a maximum value during summer. It is also found that during the period when sun does not set, the NO2 column exhibits a diurnal variation, with a peak around noon and lower values in the morning and afternoon hours. Using a simple steady-state chemical reaction scheme, an attempt has been made to explain these features.  相似文献   

4.
Zonal mean mixing ratios of ozone and NO2 measured by SAGE II on several days in March and April, 1985 are compared against zonal means for this time of year previously measured by SAGE I, SBUV, and LIMS. After allowing for calculated diurnal variations of these gases, agreement within 15% is found for ozone and 20% for NO2. It is noted that the profile error bars given on the SAGE II data tapes need to be carefully interpreted and that the measured tropical variances suggest that these error bars are being somewhat overestimated. Planetary waves in both ozone and NO2 in the middle stratosphere should be derivable from the SAGE II measurements.  相似文献   

5.
NO2 has been measured from balloons, plane and ground during Map/Globus Campaign in Europe in 1983. The results have shown an agreement between in situ and remote sensing techniques in the lower stratosphere, but some divergence at higher altitude. Part of the differences might be due to unknown experimental systematic errors and part to real atmospheric variations as the observations were not performed on the same day. In order to improve the knowledge of the instruments performances and to evaluate the NOx stratospheric budget a new field campaign has been set up in Europe in 1985. Simultaneous in situ and balloons, ground and satellites remote sensing observations of NO and NO2 were obtained, covering a 24 H period.  相似文献   

6.
Stratospheric concentrations of OH have been derived from LIMS measurements of minor constituents. Two methods have been used. Assuming that HNO3 and NO2 are in photochemical steady state, LIMS measurements of these species, with knowledge of appropriate rate constants and a calculation of the HNO3 photolysis rate, allow nearly global fields of OH to be derived. The derived profiles show satisfactory agreement with observations. As a check on our method, OH has also been derived by calculations of its sources and sinks using LIMS measurements of H2O. The two methods agree extremely well in low latitudes. At higher latitudes the agreement is less satisfactory. This is discussed in terms of the diurnal behaviour of the species and the time constant of the HNO3/NO2 equilibrium.  相似文献   

7.
Thermospheric infrared radiance at 4.3 μm is susceptible to the influence of solar-geomagnetic disturbances. Ionization processes followed by ion-neutral chemical reactions lead to vibrationally excited NO+ (i.e., NO+(v)) and subsequent 4.3 μm emission in the ionospheric E-region. Large enhancements of nighttime 4.3 μm emission were observed by the TIMED/SABER instrument during the April 2002 and October–November 2003 solar storms. Global measurements of infrared 4.3 μm emission provide an excellent proxy to observe the nighttime E-region response to auroral dosing and to conduct a detailed study of E-region ion-neutral chemistry and energy transfer mechanisms. Furthermore, we find that photoionization processes followed by ion-neutral reactions during quiescent, daytime conditions increase the NO+ concentration enough to introduce biases in the TIMED/SABER operational processing of kinetic temperature and CO2 data, with the largest effect at summer solstice. In this paper, we discuss solar storm enhancements of 4.3 μm emission observed from SABER and assess the impact of NO+(v) 4.3 μm emission on quiescent, daytime retrievals of Tk/CO2 from the SABER instrument.  相似文献   

8.
The purpose of the Nimbus 7 LIMS experiment was to sound the composition and structure of the upper atmosphere and provide data for study of photochemistry, radiation, and dynamics processes. Vertical profiles were measured of temperature and ozone (O3) over the 10-km to 65-km range and water vapor (H2O), nitrogen dioxide (NO2), and nitric acid (HNO3) over the 10-km to ~50-km range. Latitude coverage extended from 64°S to 84°N. Several general features of the atmosphere have emerged from data analyses thus far. Nitrogen dioxide exhibits rapid latitudinal variations in winter and shows hemispheric asymmetry with generally higher vertical column amount in the summer hemisphere. HNO3 data show that this gas is highly variable with altitude, latitude, and season. Smallest mixing ratios occur in the tropics, and the largest values occur in the high latitude winter hemisphere. The results show that O3, NO2, and HNO3 are strongly affected during a stratospheric warming. There is a persistently low water vapor mixing ratio in the tropical lower stratosphere (~2–3 ppmv), a poleward gradient at all times in the mission, and evidence of increasing mixing ratio with altitude at tropical and middle latitudes.  相似文献   

9.
Statistical mid-latitude models of altitude distribution of temperature, water vapor, ozone, carbon dioxide and trace gases (CO, CH4, N2O, NO, NO2) are considered. The mean characteristics of altitude profiles of these parameters, as well as their time and space variability, have been taken into account. The statistical regional models were constructed using a temperature-humidy complex. The considered statistical mid-latitude models have been constructed as applied to solutions of the problems on remote sounding of the atmosphere and underlying surface from outer space.  相似文献   

10.
A preliminary analysis of high-resolution infrared spectra of the aurorally dosed lower thermosphere above Poker Flat Research Range (PFRR), Alaska, obtained by an uplooking cryogenic field-widened interferometer (FWI) is presented. Both models and spectral-fitting/resolution-enhancement methods are used to discuss the behavior of NO, CO, NO+, and CO2 v3 vibrational bands in the high-latitude thermosphere.  相似文献   

11.
Measurements of the principal ion species of the F1- and F2- regions have been used to develop an empirical model of the ion composition for altitudes between 150 and 500 km. The species measured by the S3-1 satellite include N+, O+, N2+, NO+ and O2+. The data were obtained near the minimum of the solar cycle, thus limited information on the ionospheric variation with solar flux is available. However, the range of latitude, altitude, local time and geomagnetic activity does provide a useful basis for modeling the F-region. The ion composition measurements have been used to provide a model for relative ion composition which is compatible with the total ion density from the International Reference Ionosphere model.  相似文献   

12.
An ion model of the lower ionosphere is proposed. It consists of four positive ions: O2+, NO+ and two cluster ions - a simpler CI1 and a more complex CI2. This model well explains the normal component of the winter anomaly (WA) in the D-region, which is recorded by absorption measurements on short radiowaves and rocket experiments at middle (40°N) and high (70°) latitudes. The higher values of the electron density during the winter appear as a result of the lower recombination because of smaller rates of cluster ion formation, i.e. the normal WA can be explained and modelled by the regular seasonal variations of composition, temperature and density.  相似文献   

13.
Recent in situ measurements with balloon borne quadrupole mass spectrometers, between 20 and 45 km altitude, are reviewed and discussed.The major stratospheric positive ions observed are proton hydrates [H+(H2O)n] and non proton hydrates of the form H+Xm(H2O)2. The data analysis allows a derivation of the vertical mixing ratio profile of X (most probably CH3CN), which is compared with recent model calculations. From negative ion composition data, showing the presence of NO3? and HSO4? cluster ions, the density of sulfuric acid in the stratosphere is deduced. The implications of these findings on our understanding of the sulfur chemistry is briefly treated.Finally some other aspects such as contamination, cluster break up and the use of stratospheric ion mass spectra for determination of thermochemical data and other minor constituents are discussed.  相似文献   

14.
We have conducted a feasibility study for the geostationary monitoring of the diurnal variation of tropospheric NO2 over Tokyo. Using NO2 fields from a chemical transport model, synthetic spectra were created by a radiative transfer model, SCIATRAN, for summer and winter cases. We then performed a Differential Optical Absorption Spectroscopy (DOAS) analysis to retrieve NO2 slant column densities (SCDs), and after converting SCDs into vertical column densities (VCDs), we estimated the precision of the retrieved VCDs. The simulation showed that signal-to-noise ratio (SNR) ? 500 is needed to detect the diurnal variation and that SNR ? 1000 is needed to observe the local minimum occurring in the early afternoon (LT13–14) in summer. In winter, the detection of the diurnal variation during LT08–15 needs SNR ? 500, and SNR ? 1000 is needed if early morning (LT07) and early evening (LT16) are included. The currently discussed sensor specification for the Japanese geostationary satellite project, GMAP-Asia, which has a horizontal resolution of 10 km and a temporal resolution of 1hr, has demonstrated the performance of a precision of several percent, which is approximately corresponding to SNR = 1000–2000 during daytime and SNR ? 500 in the morning and evening. We also discuss possible biases caused by the temperature dependence of the absorption cross section utilized in the DOAS retrieval, and the effect of uncertainties of surface albedo and clouds on the estimation of precisions.  相似文献   

15.
Data from geostationary operational environmental satellite (GOES) series were used to identify intense solar energetic particle (SEP) events occurred during the solar activity cycle no. 23. We retrieved O3, NO, NO2, HNO3, OH, HCl and OHCl profiles coming from different satellite sensors (solar occultation and limb emission) and we looked for the mesospheric/stratospheric response to SEPs at high terrestrial latitudes. The chemistry of the minor atmospheric components is analysed to evaluate the associated odd nitrogen (NOx) and odd hydrogen (HOx) production, able to cause short (h) and medium (days) term ozone variations. We investigated the effects of SEPs on the polar atmosphere in three different seasons, i.e., January 2005, April 2002 and July 2000. The inter-hemispheric variability of the ozone, induced by the SEP series of January 2005, has been compared with the effects connected both to larger and quite similar events. We found that during SEP events: (i) solar illumination is the key factor driving SEP-induced effects on the chemistry of the polar atmosphere; (ii) even events with limited particle flux in the range 15–40 MeV are able to change the abundance of the minor constituents in the mesosphere and upper stratosphere.  相似文献   

16.
Soybean [Glycine max (L.) Merr.] is one of the plant species selected within the European Space Agency (ESA) Micro-Ecological Life Support System Alternative (MELiSSA) project for hydroponic cultivation in Biological Life Support Systems (BLSSs), because of the high nutritional value of seeds. Root symbiosis of soybean with Bradirhizobium japonicum contributes to plant nutrition in soil, providing ammonium through the bacterial fixation of atmospheric nitrogen. The aim of this study was to evaluate the effects of two hydroponic systems, Nutrient Film Technique (NFT) and cultivation on rockwool, and two nitrogen sources in the nutrient solution, nitrate (as Ca(NO3)2 and KNO3) and urea (CO(NH2)2), on root symbiosis, plant growth and seeds production of soybean. Plants of cultivar ‘OT8914’, inoculated with B. japonicum strain BUS-2, were grown in a growth chamber, under controlled environmental conditions.  相似文献   

17.
Large enhancements in the 4.3 micron infrared radiance have been observed since the early 1970's. Auroral photochemical models predict large enhancements in the populations of NO+(ν) and CO2 v3 that radiate in the 4.3 micron region. The strong 4.26 micron band of 12C16O2 is largely self-absorbed in the 90–110 km region with limb-viewing line-of-sight (LOS) optical depths at line center approaching 1000. Line-by-line calculations of the 626 isotope (001-000) transition and weak bands (636, 627, 628, and the 626 011-010 hot band) are necessary in order to calculate accurate limb spectra. The large effect of radiative transfer of the CO2 lines means that their contribution to the limb spectra compared to that of the optically thin NO+(Δν=1) lines is a sensitive function of the geometry of the auroral arc along the LOS.  相似文献   

18.
The positive ion composition and electron density were measured in the lower ionosphere above Kiruna in salvo A of CAMP (Cold Arctic Mesopause Project). The CAMP/P (S37/P) payload carrying a magnetic ion spectrometer, positive ion and electron probes, and propagation experiments was launched on 3 August 1982 2332 UT during extended Noctilucent Clouds (NLC) and auroral activities over Kiruna. The measured electron density was 5×103cm?3 at 80 km and 2.5×105cm?3 at 90 km. The increase of ion and electron densities in the D- and E-region during twilight was caused by precipitating auroral particles. The height distribution of the positive ions measured by the mass spectrometer in the mass range 19–280 amu is different from a winter flight with similar auroral conditions. Below 85.5 km proton hydrates H+(H2O)3 ? H+(H2O)8 were the dominant ions. The heaviest proton hydrates H+(H2O)7 and H+(H2O)8 were most abundant at 82–85.5 km, the altitude of visible NLC. Above 85.5 km O2+ and NO+ became dominant. A small metal ion layer was observed between 90.5–93 km with a maximum ion density of 10% of the total positive ion density at 91 km altitude. The metal ion density disappeared within about a km below 90.5 km.  相似文献   

19.
To investigate the feasibility of new satellite observations, including air quality (AQ) observations from geostationary (GEO) orbit, it is essential to link the measurement precision (ε) with sensor specifications in advance. The present study attempts to formulate the linkage between ε and specifications of a UV/visible sensor (signal-to-noise ratio (SNR), full width at half maximum (FWHM) of the slit function, and sampling ratio (SR)) on a GEO satellite. A sophisticated radiative transfer model (JACOSPAR) is used to calculate synthetic radiance spectra that would be measured by a UV/visible sensor observing the atmosphere over Tokyo (35.7°N, 139.7°E) from GEO orbit at 120°E longitude. The spectra, modified according to given sensor specifications, are analyzed by the differential optical absorption spectroscopy technique to estimate the ε for slant column densities of O3 and NO2. We find clear relationships: for example, the ε of the O3 slant column density (molecules cm−2) and SNR at 330 nm are linked by the equation log(ε) = −1.06 · log(SNR) + 20.71 in the UV region, and the ε of the NO2 slant column density and SNR at 450 nm are linked by log(ε) = −0.98 · log(SNR) + 18.00, at a FWHM = 0.6 nm (for the Gaussian slit function) and SR = 4. The relationships are mostly independent of other specifications (e.g., horizontal and temporal resolutions), as they affect ε primarily through SNR, providing constraints in determining the optimal SNR (and alternatively FWHM and SR) for similar UV/visible sensors dedicated for AQ studies.  相似文献   

20.
The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) measures scattered sun light also in limb viewing mode (i.e. tangential to Earth’s surface and its atmosphere), which allows determining vertical profiles of atmospheric trace gases. First results on the retrieval of NO2, BrO and OClO profiles from the SCIAMACHY Limb measurements are presented and compared to independent satellite and balloon borne observations.  相似文献   

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