Developing a stratospheric climatology from NMC analyses

The National Meteorological Center of the National Oceanic and Atmospheric Administration (NOAA) has archived global, daily synoptic analyses and computer gridded fields of geopotential height and temperature for 8 stratospheric pressure levels (70, 50, 30, 10, 5, 2, 1 and 0.4 mb) since the Autumn of 1978. More restricted analyses are available since 1964. The fields are discussed, with special emphasis on improvement of the data bases and analysis procedures. Included in the discussions are screening procedures for the climatological data base. Examples are given with regard to monthly mean energy, wind and hemispheric temperature patterns calculated as the initial development of a stratospheric dynamic climatology.     

Workshops on comparison of data and derived dynamical quantities during northern hemisphere winters

This paper reports on three workshops held by the PMP-1 working group in order to intercompare sources of middle atmosphere data on meteorological quantities. The aim is to assess the data sources, firstly to help users of the data to make best use of the available information, and secondly to identify problems that may be corrected.     

A survey over the PMP-1 winters 1978/79–1981/82 in comparison with earlier winters

The main features of the “PMP-1 Winters” are summarized and compared with information available on earlier winters, dating back partly till the winter 1951/52. The emphasis is put on a comparison of the stratospheric temperatures over the polar region and of the development of the planetary-scale waves 1 and 2. A possible modulation of these waves by the QBO (Quasi-Biennial Oscillation) and by the sunspot cycle is discussed briefly.     

Impact of four dimensional assimilation of satellite data on long-range simulations over the Indian region during monsoon 2006

A number of experiments were conducted to study the impact of updating model basic fields by satellite data (Quick Scatterometer (QSCAT) surface winds and Atmospheric Infrared Sounder (AIRS) temperature and humidity profiles) on long-range simulation during the Indian summer monsoon 2006. The Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) mesoscale model version5 (MM5) and its four dimensional data assimilation (FDDA) technique was used for the numerical simulations. The spatial distribution and temporal variation in model simulated basic meteorological parameters and rainfall were verified against the observed fields from National Center for Environmental Prediction (NCEP) analysis and Tropical Rainfall Measuring Mission (TRMM), respectively. The overall analysis of the results from QSCAT surface wind assimilation as compared to control simulation (CNT; without the satellite data assimilation) suggest that a better representation of a single level wind field during model integration fail to make significant improvement in the model simulation both in the basic meteorological parameters and rainfall. The assimilation of temperature and humidity profiles from the AIRS during model integration significantly improved the rainfall prediction during monsoon period. It is found that the improvement in rainfall prediction is attributed to improved thermodynamics structure due to AIRS profile assimilation and the degree of improvement is more in temperature prediction as compared to humidity prediction. It is also found that the prediction over the regions, such as south west part of India and foothills of Himalaya, where a complex orography exists, is not significantly benefited from satellite data assimilation which highlights the need of improvement in the model in addition to a better representation of atmospheric state.     

Satellite measurements of atmospheric composition: Three years' observations of CH4 and N2O

The stratospheric and mesospheric sounder (SAMS) was launched in October 1978 on the NIMBUS 7 satellite. Between then and its eventual failure in June 1983 the instrument was used to collect over four years of radiance data from which atmospheric temperature and the abundances of a number of minor constituents have been derived. The paper will present fields of CH₄ and N₂O between 50S and 70N derived from SAMS data for the period 1979–1981. Global distributions of CH₄ and N₂O will be presented in various forms and the observed seasonal changes and interannual variability will be described. The paper will compare the SAMS CH₄ and N₂O data with model predictions and will comment upon some other areas of interest.     

Estimation of vertically integrated water vapor in Hungary using MODIS imagery

Information about the amount and spatial structure of atmospheric water vapor is essential in understanding meteorology and the Earth environment. Space-borne remote sensing offers a relatively inexpensive method to estimate atmospheric water vapor in the form of integrated water vapor (IWV). The research activity reported in the present paper is based on the data acquired by the HRPT/MODIS (High Resolution Picture Transmission, MODerate resolution Imaging Spectroradiometer) receiving station established in Budapest (Hungary) by the Space Research Group of the Eötvös Loránd University. Integrated water vapor is estimated by the remotely sensed data of the MODIS instrument with different methods and also by the operational numerical weather prediction model of the European Centre for Medium-Range Weather Forecasts (ECMWF). Radiosonde data are used to evaluate the accuracy of the different IWV fields though it has been pointed out that the in situ data also suffers from uncertainties. It was found that both the MODIS and the ECMWF based fields are of good accuracy. The satellite data represent finer scale spatial structures while the ECMWF data have a relatively poor spatial resolution. The high quality IWV fields have proved to be useful for radiative transfer studies such as the atmospheric correction of other satellite data from times different than the overpass times of satellites Terra/Aqua and the forecast times of the model data. For this purpose the temporal variability of IWV is scrutinized both using ECMWF and MODIS data. Taking advantage of Terra and Aqua overpasses, the mean rate of change of IWV estimated by the near infrared method was found to be 0.47 ± 0.45 kg m⁻² h⁻¹, while it was 0.13 ± 0.65 kg m⁻² h⁻¹ based on the infrared method. The numerical weather prediction model’s analysis data estimated −0.01 ± 0.13 kg m⁻² h⁻¹ for the mean growth rate, while using forecast data it was 0.24 ± 0.18 kg m⁻² h⁻¹. MODIS data should be used when available for the estimation of the IWV in other studies. If no satellite data are available, or available data are only from one overpass, ECMWF based IWV can be used. In this case the analysis fields (or the satellite field) should be used for temporal extrapolation but the rate of change should be calculated from the forecast data due to its higher temporal resolution.     

利用掩星温度数据推算大气月平均纬向风场

为了弥补中高层大气风场探测数据的不足，对2007年COSMIC全球掩星在20～60km高度内的温度数据进行网格化插值，利用梯度风计算方法，计算得到20～60km高度内的月平均纬向风场，分别与ECMWF再分析数据和HWM07模式进行对比分析.结果表明，利用COSMIC温度数据计算得出的纬向风与ECMWF的纬向风十分接近，而与HWM07结果有一定差异，但总体变化趋势一致.与ECMWF再分析数据相比，利用COSMIC温度数据计算的月平均纬向风场平均偏差为-1.50～-0.08m·-1，标准差为1.50～11.95m·-1.与HWM07模式风场相比，利用COSMIC温度计算的月平均纬向风场平均偏差为-0.83～1.21m·-1，标准差为3.69～11.14m·-1.      

Catalogue of gamma-bursts detected by the Soviet-French experiment “signe 2M” (Venera-11, 12 and Prognoz-7)

This catalogue includes 49 confirmed gamma-ray bursts recorded by the Signe-2M experiment over the period September 1978 – January 1980. This Soviet-French experiment was launched on the three Soviet spacecraft Venera-11, Venera-12, and PROGNOZ-7. The PROGNOZ-7 spacecraft recorded bursts from November 1978 to May 1979. The Venera interplanetary spacecraft operated with short interruptions.The catalogue gives the histories of selected bursts with a time resolution of 1/64 s, which have never appeared in the literature. These time histories demonstrate the difference between and temporal peculiarities of these events. Table 1 summarizes precise burst arrival times at the spacecraft and the coordinates of the spacecraft at those times.     

The role of the solar magnetic field systems in modulating the solar irradiance

Variations of indices that characterize various systems of the large-scale solar magnetic field (LSSMF) - magnetic field multipoles of different order, LSSMF energy index, index of the effective solar multipole, etc.- are compared with variations of the solar irradiance in different frequency ranges during 1978–1996. The role of the local and global magnetic fields in modulating the solar irradiance is investigated in various time intervals, in particular, in different phases of the 11-year solar cycle.     

Hemispheric differences in the earth radiation budget derived from Nimbus-7 related to climate studies

Earth Radiation Budget (ERB) data from Nimbus-7 over the period November 1978 – June 1980 has consistently shown strong hemispheric differences when analyzed over different temporal and spatial scales. Hemispheric variations in time latitude cross sections of net and emitted radiation were found to be caused by changes in the Earth-Sun distance and continental effects.Maps of annual range for the entire Earth calculated from monthly averages showed areas of high and low variability of the different ERB parameters. The ERB of these regional areas were examined and most of the variability was found to lay in the large amplitude of the annual solar cycle. Variations in the global annual cycle of albedo /1/ are studied with respect to differences in latitudinal averaged albedo. The anomaly in the annual cycle of global averaged albedo was found to be caused by tropical albedo changes.     

Merging Landsat and spaceborne radar data over Tunisia

Synthetic Aperture Radar data were acquired over Tunisia by Seasat in Aug. 1978 and by SIR-A in Nov. 1981. The radar images are contrasted to the Landsat scenes overlapping the same area. The Landsat images were taken in Aug. 1978 and in Sept. 1981. In this study, subareas of the SIR-A and MSS images are registered to the corresponding Seasat data (1313 lines by 1970 samples). The test site is located East of Kairouan, Tunisia. It is a low relief area with subdesertic climatic conditions. This region was selected for it has been surveyed by both Seasat and SIR-A providing perpendicular radar illumination directions. The multispectral and multitemporal coregistered data set enables comparisons between the systems (radar versus MSS, and Seasat versus SIR-A), and change detection in the desertification processes and on the surface of the playas.     

Early results based on the stratospheric channels of TOVS on the TIROS-N series of operational satellites

TOVS (TIROS Operational Vertical Sounder) comprises the three radiometers HIRS-2 (High resolution Infra Red Sounder Mod 2), MSU (Microwave Sounding Unit) and SSU (Stratospheric Sounding Unit) mounted on the TIROS-N series of operational spacecraft. Data from these sounders have been available since October 1978 and the series should continue to beyond 1985. The derivation and assessment of stratospheric geopotential height fields from these sounders, with particular reference to the SSU, are described. Measurements of stratospheric diurnal temperature effects and plots of zonally meaned brightness temperatures over a 450 day period are also presented.     

Solar cycle effects upon the relationship of Ne and Te in the F-region

Employing Atmsophere Explorer-C measurements made in 1974, just prior to solar minimum, Brace and Theis /1/ demonstrated that a remarkably consistent inverse relationship existed between the electron density N_e and temperature T_e in the F-region. In this paper we use later data from AE-C, taken when solar activity was rising (1975–1978), and Dynamics Explorer-2 data taken at solar maximum (1981), to examine how the temperature and density relationship changes with solar activity. We find that the solar maximum T_e is a factor of two larger than the solar minimum T_e for the same values of N_e. T_e does not necessarily increase with solar activity, however, because N_e increases enough to approximately cancel the effect of higher solar extreme ultraviolet heating. We find that the effect of solar activity can be accounted for by a simple function of the F_10.7 cm index that multiplies the solar minimum equation of Brace and Theis /1/.     

Statistical parameters of nonisothermal lower ionospheric plasma in the electrically active mesosphere

The large V/m electric fields inherent in the lower mesosphere play an essential role in lower ionospheric electrodynamics. They must be the cause of large variations in the electron temperature and the electron collision frequency and consequently of the transition of the ionospheric plasma in the lower part of the D region into a nonisothermal state. This study is based on the datasets on large mesospheric electric fields collected with the 2.2-MHz radar of the Institute of Space and Atmospheric Studies, University of Saskatchewan, Canada (52°N geographic latitude, 60.4°N geomagnetic latitude), and with the 2.3-MHz radar of the Kharkiv V. Karazin National University, Ukraine (49.6°N geographic latitude, 45.6°N geomagnetic latitude). The statistical analysis of these data is presented by [Meek, C.E., Manson, A.H., Martynenko, S.I., Rozumenko, V.T., Tyrnov, O.F. Remote sensing of mesospheric electric fields using MF radars. J. Atmos. Solar-Terr. Phys. 66, 881–890, 2004. 10.1016/j.jastp.2004.02.002]. The large mesospheric electric fields in the 60–67-km altitude range are experimentally established to follow a Rayleigh distribution in the 0 < E < 2.5 V/m interval. These data have permitted the resulting differential distributions of relative disturbances in the electron temperature, θ, and the effective electron collision frequency, η, to be determined. The most probable θ and η values are found to be in the 1.4–2.2 interval, and hence the nonstationary state of the lower part of the D region needs to be accounted for in studying processes coupling the electrically active mesosphere and the lower ionospheric plasma.     

The measurement of water vapour in thermal emission on studies of nimbus-7 stratoprobe flights for correlative studies of nimbus-7

A scanning infrared radiometer used to measure nitric acid was flown on the STRATOPROBE Flight of November 8, 1978. Using the observed thermal emission from 6.5 to 7.4 microns during the balloon ascent, a water vapour profile has been derived using a band model of the water vapour lines in this spectral region. The resulting profile has a minimum of 3.3 ppmv at the tropopause and then rises to a value of 5 ppmv by 30 km. The profile is comparable to the profile from another water vapour instrument from the National Physical Laboratory which was flown on the LIP balloon payload on the same day. A coincident profile from the LIMS experiment on NIMBUS 7 was also obtained since the STRATOPROBE experiment was flown as a correlative measurement for the LIMS experiment.     

Distribution of chlorophyll and harmful algal blooms (HABs): A review on space based studies in the coastal environments of Chinese marginal seas

Monitoring of spatial and temporal distribution of chlorophyll (Chl-a) concentrations in the aquatic milieu is always challenging and often interesting. However, the recent advancements in satellite digital data play a significant role in providing outstanding results for the marine environmental investigations. The present paper is aimed to review ‘remote sensing research in Chinese seas’ within the period of 24 years from 1978 to 2002. Owing to generalized distributional pattern, the Chl-a concentrations are recognized high towards northern Chinese seas than the southern. Moreover, the coastal waters, estuaries, and upwelling zones always exhibit relatively high Chl-a concentrations compared with offshore waters. On the basis of marine Chl-a estimates obtained from satellite and other field measured environmental parameters, we have further discussed on the applications of satellite remote sensing in the fields of harmful algal blooms (HABs), primary production and physical oceanographic currents of the regional seas. Concerned with studies of HABs, satellite remote sensing proved more advantageous than any other conventional methods for large-scale applications. Probably, it may be the only source of authentic information responsible for the evaluation of new research methodologies to detect HABs. At present, studies using remote sensing methods are mostly confined to observe algal bloom occurrences, hence, it is essential to coordinate the mechanism of marine ecological and oceanographic dynamic processes of HABs using satellite remote sensing data with in situ measurements of marine environmental parameters. The satellite remote sensing on marine environment and HABs is believed to have a great improvement with popular application of technology.     

Calibration results obtained with Liulin-4 type dosimeters.

The Mobile Radiation Exposure Control System's (Liulin-4 type) main purpose is to monitor simultaneously the doses and fluxes at 4 independent places. It can also be used for personnel dosimetry. The system consists of 4 battery-operated 256-channel dosimeters-spectrometers. We describe results obtained during the calibrations of the spectrometers at the Cyclotron facilities of the University of Louvain, Belgium and of the National Institute of Radiological Sciences-STA, Chiba, Japan with protons of energies up to 70 MeV. The angular sensitivities of the devices are studied and compared with Monte-Carlo predictions. We also present the results obtained at the HIMAC accelerator with 500 MeV/u Fe ions and at the CERN high energy radiation reference fields. Records made during airplane flights are shown and compared with the predictions of the CARI-6 model.     

Long-term observations of the trapped high-energy proton population (L < 4) by the NOAA Polar Orbiting Environmental Satellites (POES)

The Space Environment Monitor (SEM) onboard the NOAA POES satellites has been measuring the near-Earth charged particle environment since 1978, providing an extensive database that can be used for studying the long-term behavior of this population of trapped particles. POES stands for Polar Orbiting Environmental Satellite. These satellites orbit at ∼840 km altitude and at an inclination of 98°. The SEM-1 instrument was flown on the POES satellites beginning in 1978 with TIROS-N and NOAA-6 in 1979 and continuing to NOAA-14 launched in 1995 with the exception of NOAA-9 and NOAA-11 (NOAA-13 failed shortly after launch). Its replacement, SEM-2, has flown on the POES NOAA-15, -16, and -17 satellites (from 1998). Here we present the results of a study on the statistical variations of the high-energy trapped proton environment. Among the detectors in SEM, the four SEM-2 omni-directional proton detectors for energies >16 MeV, >36 MeV, >70 MeV, and >140 MeV provide the data most relevant to this study.     

面向星载应用的空间域四叉树层次化图像压缩算法

为满足卫星应用领域对高分辨率遥感图像实时传输与存储的要求，针对该类图像特征，提出基于空间域四叉树数据结构的图像数据亚采样与多模式自适应预测编码相结合的压缩算法。该算法使用四叉树数据结构与三种预测编码模式，针对图像块纹理差别，自适应地选取相应的亚采样与量化编码方式，通过采样方式与量化方式的变化，达到保存高分辨率遥感图像细节与小目标绝不丢失的要求，实现了对遥感图像中目标边缘和变化剧烈的细节的高保真效果，同JPEG相比，恢复图像峰值信噪更高、图像纹理细节保持能力更强。利用具有可编程序门阵列器件物理实现上述算法，获得高速图像压缩专用芯片，该芯片数据处理速度达到288Mbit／s，功耗低于1W。