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111.
This paper studies the response of the middle atmosphere to the 11-year solar cycle. The study is based on numerical simulations
with the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), a chemistry climate model that resolves the atmosphere
from the Earth’s surface up to about 250 km. Results presented here are obtained in two multi-year time-slice runs for solar
maximum and minimum conditions, respectively. The magnitude of the simulated annual and zonal mean stratospheric response
in temperature and ozone corresponds well to observations. The dynamical model response is studied for northern hemisphere
winter. Here, the zonal mean wind change differs substantially from observations. The statistical significance of the model’s
dynamical response is, however, poor for most regions of the atmosphere. Finally, we discuss several issues that render the
evaluation of model results with available analyses of observational data of the stratosphere and mesosphere difficult. This
includes the possibility that the atmospheric response to solar variability may depend strongly on longitude. 相似文献
112.
K. Kodera 《Space Science Reviews》2006,125(1-4):319-330
This paper reviews the solar influence on climate through stratospheric dynamical processes. There are two possible processes,
both being a consequence of the wave-mean flow interaction in the upper stratosphere. One involves changes in the vertical
propagation of planetary waves and the resultant tropospheric circulation change in the extratropics of the winter hemisphere.
The other involves change in the global meridional circulation in the stratosphere and associated convective activity change
in the tropics. These processes have been discussed on an 11-year solar cycle, but they are also applicable for centennial-scale
solar influence on climate. 相似文献
113.
M.N. Kulkarni A.K. Kamra 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
A theoretical model is developed for calculating the vertical distribution of atmospheric electric potential in exchange layer of maritime clean atmosphere. The transport of space charge in electrode layer acts as a convective generator in this model and plays a major role in determining potential distribution in vertical. Eddy diffusion is the main mechanism responsible for the distribution of space charge in vertical. Our results show that potential at a particular level increases with increase in the strength of eddy diffusion under similar conditions. A method is suggested to estimate columnar resistance, the ionospheric potential and the vertical atmospheric electric potential distribution in exchange layer from measurements of total air-earth current density and surface electric field made over oceans. The results are validated and found to be in very good agreement with the previous aircraft measurements. Different parameters involved in the proposed methodology can be determined either theoretically, as in the present work, or experimentally using the near surface atmospheric electrical measurements or using some other surface-based measurement technique such as LIDAR. A graphical relationship between the atmospheric eddy diffusion coefficient and height of exchange layer obtained from atmospheric electrical approach, is reported. 相似文献
114.
G. Salamunićcar 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
The Mathematical Statistics Theory (MST) and the Mathematical Theory of Stochastic Processes (MTSP) are different branches of the more general Mathematical Probability Theory (MPT) that can be used to investigate physical processes through mathematics. Each model of a stochastic process, according to MTSP, can provide one or more interpretations in the MST domain. A large body of work on impact crater statistics according to MST exists, showing cumulative crater frequency (N km−2) as a function of age (years) for some particular crater diameter. However, this is only one possible representation in the MST domain of the bombardment of the planetary surface modeled as a stochastic process according to MTSP. The idea that other representations are possible in the MST domain of the same stochastic process from MTSP has been recently presented. The importance of the approach is that each such mathematical-based interpretation can provide a large amount of new information. Coupled with MOLA data, Topography-Profile Diagrams (TPD) are one of the many examples that can provide a large amount of new information regarding the history of Mars. TPD consists of: (1) Topography-Profile Curve (TPC), which is a representation of the planet’s topography, (2) Density-of-Craters Curve (DCC), which represents density of craters, (3) Filtered-DCC (FDCC), which represents DCC filtered by a low-pass filter, included with the purpose of reducing the noise, and (4) Level-of-Substance-Over-Time Curve (LSOTC), which represents interpretation of the influence on the distribution of craters shown by FDCC. TPC uniquely corresponds to the computation of TPD, whereas DCC depends on algorithms for computing the elevation of each crater according to the topography, center coordinates, and radius of impact crater, and FDCC relies on the architecture of the custom designed low-pass filter for filtering DCC. However, all variations of DCC and FDCC, which includes the various impact crater data sets, showed a correlation among the density of craters and elevation over 70–80% of the planet surface. Additionally, if we assume that the ocean primarily caused the noted correlation, LSOTC offers a mathematical approach for estimating topographic change of the ocean’s extent over time. Accordingly, TPD is the first new practical application of MTSP to lunar and planetary sciences, showing correlation of topography to a physical process. 相似文献
115.
Crisan Demetrescu Venera DobricaGeorgeta Maris 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Annual means of measured and reconstructed solar, heliospheric, and magnetospheric parameters are used to infer solar activity signatures at the Hale and Gleissberg cycles timescales. Available open solar flux, modulation strength, cosmic ray flux, total solar irradiance data, reconstructed back to 1700, solar wind parameters (speed and density) and the magnitude of the heliospheric magnetic field at 1 AU, reconstructed back to 1870, as well as the time series of geomagnetic activity indices (aa, IDV, IHV), going back to 1870, have been considered. Simple filtering procedures (successive 11-, 22-, and 88-year running averages and differences between them) and scaling by the standard deviation from the average value for the common interval covered by the data show that the long-discussed variation in the 20th century (a pronounced increase since ∼1900, followed by a depression in the ‘60s and a new, slower, increase) seen in the 11-year averages of parameters such as geomagnetic activity indices and reconstructed heliospheric magnetic field strength, solar wind speed, open solar flux, is a result of the superposition in data of solar activity signatures at Hale and Gleissberg cycles timescales. The Hale and Gleissberg signals were characterized and similarities and differences in the temporal behavior of the analyzed parameters at these timescales are discussed. The similarities in the studied parameters point to a common pacing source, the solar dynamo. 相似文献
116.
Darrell F. Strobel 《Space Science Reviews》2005,116(1-2):155-170
The photochemistries of the H2-He atmospheres of the gas giants Jupiter, Saturn and ice giants Uranus and Neptune and Titan’s mildly reducing N2 atmosphere are reviewed in terms of general chemical and physical principles. The thermochemical furnace regions in the deep
atmospheres and the photochemical regions of the giant planets are coupled by vertical mixing to ensure efficient recyling
of photochemical products. On Titan,mass loss of hydrogen ensures photochemical evolution of methane into less saturated hydrocarbons.
A summary discussion of major dissociation paths and essential chemical reactions is given. The chapter ends with a overview
of vertical transport processes in planetary atmospheres. 相似文献
117.
J.-F. Crétaux W. Jelinski S. Calmant A. Kouraev V. Vuglinski M. Bergé-Nguyen M.-C. Gennero F. Nino R. Abarca Del Rio A. Cazenave P. Maisongrande 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
An accurate and continuous monitoring of lakes and inland seas is available since 1993 thanks to the satellite altimetry missions (Topex–Poseidon, GFO, ERS-2, Jason-1, Jason-2 and Envisat). Global data processing of these satellites provides temporal and spatial time series of lakes surface height with a decimetre precision on the whole Earth. The response of water level to regional hydrology is particularly marked for lakes and inland seas in semi-arid regions. A lake data centre is under development at by LEGOS (Laboratoire d’Etude en Géophysique et Océanographie Spatiale) in Toulouse, in coordination with the HYDROLARE project (Headed by SHI: State Hydrological Institute of the Russian Academy of Science). It already provides level variations for about 150 lakes and reservoirs, freely available on the web site (HYDROWEB: http://www.LEGOS.obs-mip.fr/soa/hydrologie/HYDROWEB), and surface-volume variations of about 50 big lakes are also calculated through a combination of various satellite images (Modis, Asar, Landsat, Cbers) and radar altimetry. The final objective is to achieve in 2011 a fully operating data centre based on remote sensing technique and controlled by the in situ infrastructure for the Global Terrestrial Network for Lakes (GTN-L) under the supervision of WMO (World Meteorological Organization) and GCOS (Global Climate Observing System). 相似文献
118.
Aerosol-Cloud Interactions Control of Earth Radiation and Latent Heat Release Budgets 总被引:2,自引:0,他引:2
D. Rosenfeld 《Space Science Reviews》2006,125(1-4):149-157
Aircraft observations and model simulations show that cloud development is strongly modulated by the impact of cloud-aerosol
interactions on precipitation forming processes. New insights into the mechanisms by which aerosols dominate the cloud cover
of marine shallow clouds suggest that feedbacks between the cloud microstructure and cloud dynamics through precipitation
processes play a major role in determining when a solid cloud cover will break up into a field of trade wind cumulus. Cloud-aerosol
interactions dominate not only the dynamics of marine shallow clouds, but also the lifetime and the vertical disposition of
latent heat of deep convective clouds over ocean and even more strongly over land. Recent coincident satellite measurements
of aerosols and cloud properties quantify the aerosol effects on cloud cover and radiative forcing on regional and global
scales. The shapes of the satellite retrieved relations between aerosols and cloud properties are consistent with the suggested
ways by which aerosols affect clouds via precipitation processes, particularly by affecting the intensity of the cloud vertical
air motions and its vertical development. 相似文献
119.
岳彩军 《郑州航空工业管理学院学报(管理科学版)》2007,25(1):44-47
运用经济学理论对我国沿海地区产业集群发展的经验进行分析,结果表明,地区产业集群的形成是政府采取不平衡发展战略的结果,具有比较优势的主导产业又是形成产业集群网络式的、具有不断创新能力特征的主要依托,完善的市场运行机制、良好的投资环境是产业集群发挥极化效应、扩展效应和回程效应的基础,同时又是带动区域经济发展的动力。 相似文献
120.
An increasing number of studies indicate that variations in solar activity have had a significant influence on Earth's climate.
However, the mechanisms responsible for a solar influence are still not known. One possibility is that atmospheric transparency
is influenced by changing cloud properties via cosmic ray ionisation (the latter being modulated by solar activity). Support
for this idea is found from satellite observations of cloud cover. Such data have revealed a striking correlation between
the intensity of galactic cosmic rays (GCR) and low liquid clouds (<3.2 km). GCR are responsible for nearly all ionisation
in the atmosphere below 35 km. One mechanism could involve ion-induced formation of aerosol particles (diameter range, 0.001–1.0
μm) that can act as cloud condensation nuclei (CCN). A systematic variation in the properties of CCN will affect the cloud
droplet distribution and thereby influence the radiative properties of clouds. If the GCR-Cloud link is confirmed variations
in galactic cosmic ray flux, caused by changes in solar activity and the space environment, could influence Earth's radiation
budget.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献