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1.
Total Solar Irradiance Observations   总被引：1，自引：0，他引：1  
The record of total solar irradiance (TSI) during the past 35?years has overlapping observations from space which can be merged to a composite, and three are available, namely the PMOD, the ACRIM and the IRMB composites. There are important differences between them, which are discussed in detail in order to find the best representation of solar variability during the last three cycles, for the following discussions of solar irradiance variability. Moreover, the absolute value of TSI from TIM on SORCE is 1,361?Wm?2, substantially lower than the value 1,365?Wm?2, which was observed by the classical radiometers. New results from specific experiments are now available, which are discussed in order to define the value to be used in, e.g., climate models. The most important issue regarding the recent TSI records is the low value observed during the minimum in 2009, which is 25% of a typical cycle amplitude lower than the value in 1996. The validity of this low value has been confirmed by comparing all existing TSI observations during cycle 23. On the other hand, activity indices, such as the sunspot number, the 10.7-cm radio flux (F10.7), the CaII and MgII indices and also the Ly-α irradiance or the frequency changes in low-order p modes, show a much smaller decreases relative to their respective typical cycle amplitude. It is most likely that an increasing contrast of the facular and network elements with decreasing magnetic field is responsible for this discrepancy. The value of TSI at minima is correlated with the open magnetic field of the Sun, B R,?at minima. Using B R at minima, interpolated linearly in between as a fourth component of a proxy model based on the photometric sunspot index and on the MgII index improves the explanation of the variance of TSI over the full period of the last three solar cycles to 84.7%. Results from other models are also discussed.  相似文献   

2.
Autoregressive integrated moving average (ARIMA) models are used to compare long-range temporal variability of the total solar irradiance (TSI) at the top of the atmosphere (TOA) and surface air temperature series. The comparison shows that one and the same type of the model is applicable to represent the TSI and air temperature series. In terms of the model type surface air temperature imitates closely that for the TSI. This may mean that currently no other forcing to the climate system is capable to change the random walk type variability established by the varying activity of the rotating Sun. The result should inspire more detailed examination of the dependence of various climate series on short-range fluctuations of TSI.  相似文献   

3.
Geomagnetism and Aeronomy - Reconstruction and forecasting the data series of total solar irradiation (TSI) is one of the most urgent scientific problems at the moment. In this paper, we review...  相似文献   

4.
针对电磁探测数据交叉检验时对不同卫星探测数据的时间匹配需求,本文基于DEMETER卫星时序探测数据,分析了国际参考电离层(IRI)模型模拟电子浓度(Ne)数据在不同纬度区域的误差分布特征; 同时,基于自回归移动平均(ARIMA)模型构建了Ne数据时序预测模型. 在此基础上,分析比较IRI模型与ARIMA模型在Ne数据时序预测中的优缺点,结果表明: ARIMA模型模拟预测Ne数据时间序列的相对误差在短期内较低(小于10%),且随着预测时间的增长而增大; 而IRI模型模拟预测Ne数据时间序列的相对误差不会随着预测时间的增长而增大,且在高纬度地区的预测相对误差比在中低纬度地区低.   相似文献   

5.
Summary Observations of the vertical ozone distribution over Arosa, Switzerland, have been carried out routinely since 1956 (with one two-year gap). Long-term trends of ozone concentration at different levels indicated by this series are discussed in the light of the results obtained from five years of parallel measurements with two Dobson spectrophotometers. Further substantiation of the suggested correlation between ozone concentration in the upper stratosphere and solar activity (with a two- to three-year lag of ozone against sun-spot numbers) is needed because no full agreement was obtained from the two instruments with respect to the secular variation at those top levels.  相似文献   

6.
The biological processes have been proposed as climate variability contributors. Dimethylsulfide (DMS) is the main biogenic sulfur compound in the atmosphere; it is mainly produced by the marine biosphere and plays an important role in the atmospheric sulfur cycle. Currently it is accepted that terrestrial biota not only adapts to environmental conditions but also influences them through regulations of the chemical composition of the atmosphere. In the present study we used a wavelet method to investigate the relationship between DMS, Low cloud cover (LCC), Ultraviolet Radiation A (UVA), Total Solar Irradiance (TSI) and Sea Surface Temperature (SST) in the so called pristine zone of the Southern Hemisphere. We found that the series analyzed have different periodicities which can be associated with large scale climatic phenomena such as El Niño (ENSO) or the Quasi-Biennial Oscillation (QBO), and/or to solar activity. Our results show an intermittent but sustained DMS-SST correlation and a DMSUVA anti correlation; but DMS-TSI and DMS-LCC show nonlinear relationships. The time-span of the series allow us to study only periodicities shorter than 11 years, then we limit our analysis to the possibility that solar radiation influences the Earth climate in periods shorter than the 11-year solar cycle. Our results also suggest a positive feedback interaction between DMS and solar radiation.  相似文献   

7.
This work investigates the behavior of the sunspot number and Southern Oscillation Index (SOI) signal recorded in the tree ring time series for three different locations in Brazil: Humaitá in Amaz?nia State, Porto Ferreira in S?o Paulo State, and Passo Fundo in Rio Grande do Sul State, using wavelet and cross-wavelet analysis techniques. The wavelet spectra of tree ring time series showed signs of 11 and 22?years, possibly related to the solar activity, and periods of 2–8?years, possibly related to El Ni?o events. The cross-wavelet spectra for all tree ring time series from Brazil present a significant response to the 11-year solar cycle in the time interval between 1921 to after 1981. These tree ring time series still have a response to the second harmonic of the solar cycle (5.5?years), but in different time intervals. The cross-wavelet maps also showed that the relationship between the SOI x tree ring time series is more intense, for oscillation in the range of 4–8?years.  相似文献   

8.
The direct impact of solar activity on climate has been widely studied through Total Solar Irradiance (TSI). Biological processes also impact climate and are deeply affected by TSI. Marine phytoplankton emissions into the atmosphere have been proposed to change cloud albedo through cloud formation. In this work, we use wavelet analysis to investigate the decadal relation between high-latitude concentrations of methane sulphonic acid, a product of seawater algae, and TSI. We found that some of the methane sulphonic acid main periodicities coincide with periods of solar activity periods.  相似文献   

9.
The MEPED instruments onboard the low-altitude polar orbiting NOAA/POES satellites have measured energetic particles since 1978, offering a nearly continuous series of energetic particle fluxes in the magnetosphere during three solar cycles. However, there are several problems in using these data for long-term studies, the most significant one being that the solid state detectors of the MEPED proton instruments suffer significant radiation damage. This causes the effective energy thresholds of the instrument to increase, leading to underestimated particle fluxes already a couple of years after satellite launch. Before the MEPED data can reliably be used in any long-term study the data have to be recalibrated taking into account the decay of the detectors. In this paper we present quantified estimates of the degree of radiation damage for all NOAA/POES satellites, a method for correcting the MEPED proton measurements, and give an estimate of energetic proton fluxes from 1978 to present.  相似文献   

10.
Solar irradiance models that assume solar irradiance variations to be due to changes in the solar surface magnetic flux have been successfully used to reconstruct total solar irradiance on rotational as well as cyclical and secular time scales. Modelling spectral solar irradiance is not yet as advanced, and also suffers from a lack of comparison data, in particular on solar cycle time scales. Here, we compare solar irradiance in the 220–240?nm band as modelled with SATIRE-S and measured by different instruments on the UARS and SORCE satellites. We find good agreement between the model and measurements on rotational time scales. The long-term trends, however, show significant differences. Both SORCE instruments, in particular, show a much steeper gradient over the decaying part of cycle 23 than the modelled irradiance or that measured by UARS/SUSIM.  相似文献   

11.
Data from three solar observatories (Learmonth, Holloman, and San Vito) are used to study the variations in the average number of sunspots per sunspot group. It is found that the different types of sunspot groups and the number of sunspots in these groups have different solar cycle and cycle to cycle variations. The varying ratio between the average number of sunspots and the number of sunspot groups is shown to be a real feature and not a result of changing observational instruments, observers’ experience, calculation schemes, etc., and is a result of variations in the solar magnetic fields. Therefore, the attempts to minimize the discrepancies between the sunspot number and sunspot group series are not justified, and lead to the loss of important information about the variability of the solar dynamo.  相似文献   

12.
Abstract

The effects induced on the climate by human activity have become a major issue for the new millennium. In order to arrive at sustainable conclusions it is necessary, first of all, to assess and quantify natural climatic changes. In general this is done by analysing available time series. In the case of historical hydrometeorological data sets, a comparative analysis with solar cycles is not usually conducted. This work, however, demonstrates that the effect of solar cycles observed at the Equator is also visible at middle and high latitudes with multiple periodicity of the basic solar frequency (roughly 11 years). This could well be due to the interaction between solar forcing and circulation mechanisms within the atmosphere, i.e. water-air-soil interactions coupled with anthropogenic forcing. This theory has been tested by comparing different types of historical data series with the River Po discharges and cyclic appearance of slime bloom in the Adriatic Sea.  相似文献   

13.
Analysis of the time series into trigonometric series allows the investigation of cosmic-ray (CR) intensity variations in a range of periodicities from a few days to 1 year. By this technique the amplitude and the phase of all observed fluctuations can be given. For this purpose, daily CR intensity values recorded at Climax Neutron Monitor station for the time intervals 1979–1982 and 1989–1991, which correspond to the epochs of maximum activity for solar cycles 21 and 22, respectively, have been studied. The data analysis revealed the occurrence of new periodicities, common or not, in the two solar maxima. A search of our results was done by a power spectral analysis determining independently possible systematic periodic or quasi-periodic variations. Based on the fact that during these maxima the CR intensity tracks the solar flare index better than the sunspot number, the same analysis was performed on these data, which are equivalent to the total energy emitted by the solar flares. Both analyses result in periodicities with different probability of occurrence in different epochs. Occurrence at peaks of 70, 56, 35, 27, 21 and 14- days were observed in all time series, while the periods of 140–154 and 105 days are reported only in the 21st solar maximum and are of particular importance. All of the short-term periods except of those at 27 and 154-days are recorded for first time in CR data, but they had already been observed in the solar activity parameters. Moreover, each parameter studied here has a very different power spectrum distribution in periods larger than 154 days. The possible origin of the observed variations in terms of the CR interaction in the upper atmosphere and the solar cavity dynamics is also discussed here.  相似文献   

14.
Detection of the deterministic component from noised time series is a common procedure in the solar–terrestrial coupling problem when climate is modeled, solar activity is analyzed, or a signal associated with helium is extracted. Such series are mostly generated by the superposition of different processes for which the concept of a noise component cannot be determined formally. A method based on the combination of time-series topological embedding in Euclidean space and the identification of a persistent cycle by homology theory methods is proposed. The method application is demonstrated based on actual data.  相似文献   

15.
We propose a simple model to describe the behaviour of solar quiet geomagnetic variations Sq over a long time. We assume that Sq variations can be expressed through 24-h components and their harmonics subject to three modulations: 1 year, 11 years and several tens years. We started from the observation that the spectral lines of 30-year geomagnetic data series are split in accordance with yearly modulation. Our model gives good approximation of Sq variations and discloses a striking correlation of amplitudes and phases of modulating functions with the sunspot number and 2.8 GHz solar radio emission. It is also a tool for monitoring the Sq variations.  相似文献   

16.
《水文科学杂志》2012,57(1):102-111
ABSTRACT

Water temperature monitoring is important in many scientific studies. This study compares three models of water temperature sensors (Vemco Minilog II, HOBO TidbiT and HOBO Pendant) to test the importance of: (1) using cross-calibration to minimize relative errors, (2) using cross-calibration to improve on the accuracy of less accurate sensors, and (3) protecting sensors against direct solar radiation heating. The results show that when the same sensor models are cross-calibrated, the relative error can be reduced (Vemco: 0.01°C; HOBO TidbiT: 0.02°C; and HOBO Pendant: 0.07°C). Cross-calibration can also improve less accurate sensors (HOBO TidbiT and Pendant) to similar accuracies of Vemco (±0.1°C). Finally, no evidence of solar radiation heating was observed for Vemcos (unprotected); however, HOBO TidbiT and Pendant showed heating up to 2°C (maximum). When HOBO TidbiT and Pendant are shielded (flow-through system), heating is no longer an issue.  相似文献   

17.
Present-day data on 14C and 10Be concentration in natural archives have been statistically analyzed. It has been established that it is difficult to extract information about solar activity variations on long (several Myr and longer) and, especially, short (to 30 years) time scales using radiocarbon data. It has been indicated that beryllium series bear reliable information about short-term, secular, and, probably, 1000-year variations in solar activity. Moreover, 10Be concentration in polar ice can also be used to study the internal dynamics of solar activity. It has been concluded that beryllium data are more promising than radiocarbon ones from the viewpoint of solar paleoastrophysics.  相似文献   

18.
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19.
This is a first report of combined observations form the solar instruments at the recently inaugurated German–Argentinean Solar-Observatory at El Leoncito, San Juan, Argentina. The Hα telescope (HASTA) and the mirror coronagraph (MICA) daily image the solar disk and the inner solar corona respectively with high temporal and spatial resolution. The excellent weather conditions for solar studies of the Observatory, and its south equatorial location allow a complementary summer-condition data with respect to the majority of the other observatories, mainly located in the northern hemisphere. In this paper, we present four events in order to study possible correlations between observations taken by both telescopes. Since each instrument records data in quite different temperature regimes, correlation between both set of data appears when the phenomena span a broad range of temperatures. This is explicitly shown for two of the four set of data presented here. On the other hand, the four cases are good examples of the contributions the two instruments can provide to the better understanding of the mechanisms at work in the inner solar atmosphere.  相似文献   

20.
The main aim of the work was to reliably reconstruct the change in global temperature for the last 1000 years using new methods. We have considered two approaches to obtaining composite series based on symbolic analysis and on the so-called ??principle of witnesses,?? respectively. Based on the first approach, it has been indicated that the known reconstruction proposed by Moberg et al. is preferable in the scope of the accepted symbolic analysis variant among the available reconstructions. An approach based on the eyewitness principle made it possible to reveal the years when five different reconstructions give coordinated data on a 1000-year scale. The obtained new reconstructions are in good agreement with instrumental series data on the consistent time interval of their existence.  相似文献   

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